CSS Basics: Styling Links Like a Boss

The web was founded on links. The idea that we can click/tap a link and navigate from one web page to another is how surfin’ the web become a household phrase.

Links in HTML even look different from regular text without any CSS styling at all.

See the Pen Default Link by CSS-Tricks (@css-tricks) on CodePen.

They are blue (purple if visited). They are underlined. That’s a link in it’s purest form.

But what if we want to change things up a bit? Perhaps blue doesn’t work with your website’s design. Maybe you have an aversion to underlines. Whatever the reason, CSS lets us style links just we can any other element. All we need to do is target the <a> element in our stylesheet.

Want to use a different font, change the color, remove the underline and make it all uppercase? Sure, why not?

a { color: red; text-decoration: none; text-transform: uppercase;
}

See the Pen Link With Some Style by Geoff Graham (@geoffgraham) on CodePen.

Now we’re cooking with gas! But why stop there? Let’s look at a few other ways we can style links to complete the experience.

Style Each Link State

Links have different states, meaning they adapt when we interact with them on a webpage. There are three additional states of a link that are worth considering anytime we change the default style of links:

  • Hover (:hover): When the mouse cursor is place on top of the link without a click
  • Visited (:visited): The appearance of a link that the user has clicked on the page before when the mouse cursor is not on top of it
  • Active (:active): When the link is in the process of being clicked. It might be super quick, but this is when the mouse button has been depressed and before the click is over.

Here is the same link we have been looking at. First, try hovering your mouse on top of it without clicking and notice that it becomes underlined. Then, click on the link, but leave your mouse button clicked down for a little bit to see how the active style changes the color of the link to black. Finally, let up on the mouse button and the link should turn purple before it’s technically been visited.

See the Pen Link With Styled States by Geoff Graham (@geoffgraham) on CodePen.

Links seem like a simple concept, but boy do they have a lot going on—and CSS gives us some incredible power to customize the experience!

Links as Buttons

While there is some debate about it, we can use CSS to make a text link look like a button.

Like other HTML elements, CSS can add background colors and padding to links that allow us to create the appearance of a button. Here’s our link using those techniques:

a { background-color: red; color: white; padding: 1em 1.5em; text-decoration: none; text-transform: uppercase;
}

See the Pen Link as a Button by CSS-Tricks (@css-tricks) on CodePen.

Great! Now, let’s use the state-altering powers we learned in the last section to make our faux-button more interactive. We’ll make the button dark gray on hover, black on active, and light gray on visit:

a { background-color: red; color: white; padding: 1em 1.5em; text-decoration: none; text-transform: uppercase;
} a:hover { background-color: #555;
} a:active { background-color: black;
} a:visited { background-color: #ccc;
}

See the Pen Link as a Button With Styled States by Geoff Graham (@geoffgraham) on CodePen.

Styling a link as a button and taking advantage of the states allows us to make some pretty cool effects. For example, let’s create a button with some depth that appears to get pressed when it’s active and pop back up when the click is done.

See the Pen Link as a 3D Button by Geoff Graham (@geoffgraham) on CodePen.

Oh, and Cursors!

We’ve gone into pretty great depth on style links, but there is one more component to them that we cannot ignore: the cursor.

The cursor indicates the position of the mouse on the screen. We’re pretty used to the standard black arrow:

The standard mouse cursor arrow

We can change the arrow to a hand pointer on it’s hover (:hover) state so that it’s easier to see that the link indicates it is an interactive element:

Using cursor:
pointer;
provides an interactive cue.
a:hover { cursor: pointer;
}

See the Pen Link as a 3D Button With Pointer by Geoff Graham (@geoffgraham) on CodePen.

Whew, that’s much nicer! Now, we have a pretty fancy link that looks like a button with proper interactive cues.

Leveling Up

We’ve covered quite a bit of ground here, but it merely scratches the surface of how we can control the style of links. If you’re ready to level up, then here are a few resources you can jump into from here:

  • Mailto Links – A good reference for linking up email addresses instead of webpages.
  • The Current State of Telephone Links – Did you know you can link a phone number? Well, here’s how.
  • Cursor – The CSS-Tricks reference guide for customizing the cursor.
  • When to Use the Button Element – If you’re wondering about the difference between a link button and a traditional form button, then this is a good overview with suggestions for which is better for specific contexts.
  • Button Maker – A free resource for generating the CSS for link buttons.

CSS Basics: Styling Links Like a Boss is a post from CSS-Tricks

CSS Basics: Using Multiple Backgrounds

With CSS, you can control the background of elements. You can set a background-color to fill it with a solid color, a background-image to fill it with (you guessed it) an image, or even both:

body { background-color: red; background-image: url(pattern.png);
}

Here’s an example where I’m using an SVG image file as the background, embedded right in the CSS as a data URL.

See the Pen background color and image together by Chris Coyier (@chriscoyier) on CodePen.

That’s just a single image there, repeated, but we can actually set multiple background images if we want. We do that by separating the values with commas.

body { background-image: url(image-one.jpg), url(image-two.jpg);
}

If we leave it like that, image-one.jpg will repeat and entirely cover image-two.jpg. But we can control them individually as well, with other background properties.

body { background-image: url(image-one.jpg), url(image-two.jpg); background-position: top right, /* this positions the first image */ bottom left; /* this positions the second image */ background-repeat: no-repeat; /* this applies to both images */
}

See how background-position also has comma-separated values? Those will apply individually to each image respectively. And then how background-repeat has only one value? We could have done two values in the same way, but by using just one value, it applies to both.

Here’s an example using four separate images, one in each corner, offset by a smidge:

See the Pen Example of multiple backgrounds by Chris Coyier (@chriscoyier) on CodePen.

It’s too bad you can’t rotate or flip background images or else we could have used just one. We can rotate and flip entire elements (or psuedo elements) though, so in cases like that, we can get away with using a single image!

See the Pen Flipping Image So You Can Use Just One by Chris Coyier (@chriscoyier) on CodePen.

Just a few other things to be aware of here:

  1. The stacking order of multiple background is “first is on top.”
  2. Gradients are applied through background-image, so they can be used as part of all this. For example, you could set a transparent gradient over a raster image.

See the Pen Tinted Image w/ Multiple Backgrounds by Chris Coyier (@chriscoyier) on CodePen.


CSS Basics: Using Multiple Backgrounds is a post from CSS-Tricks

CSS Basics: The Second “S” in CSS

CSS is an abbreviation for Cascading Style Sheets.

While most of the discussion about CSS on the web (or even here on CSS-Tricks) is centered around writing styles and how the cascade affects them, what we don’t talk a whole lot about is the sheet part of the language. So let’s give that lonely second “S” a little bit of the spotlight and understand what we mean when we say CSS is a style sheet.

The Sheet Contains the Styles

The cascade describes how styles interact with one another. The styles make up the actual code. Then there’s the sheet that contains that code. Like a sheet of paper that we write on, the “sheet” of CSS is the digital file where styles are coded.

If we were to illustrate this, the relationship between the three sort of forms a cascade:

The sheet holds the styles.

There can be multiple sheets all continuing multiple styles all associated with one HTML document. The combination of those and the processes of figuring out what styles take precedence to style what elements is called the cascade (That first “C” in CSS).

The Sheet is a Digital File

The sheet is such a special thing that it’s been given its own file extension: .css. You have the power to create these files on your own. Creating a CSS file can be done in any text editor. They are literally text files. Not “rich text” documents or Word documents, but plain ol’ text.

If you’re on Mac, then you can fire up TextEdit to start writing CSS. Just make sure it’s in “Plain Text” mode.

If you’re on Windows, the default Notepad app is the equivalent. Heck, you can type styles in just about any plain text editor to write CSS, even if that’s not what it says it was designed to do.

Whatever tool you use, the key is to save your document as a .css file. This can usually be done by simply add that to your file name when saving. Here’s how that looks in TextEdit:

Seriously, the choice of which text editor to use for writing CSS is totally up to you. There are many, many to choose from, but here are a few popular ones:

  • Sublime Text
  • Atom
  • VIM
  • PhpStorm
  • Coda
  • Dreamweaver

You might reach for one of those because they’ll do handy things for you like syntax highlight the code (colorize different parts to help it be easier to understand what is what).

Hey look I made some files completely from scratch with my text editor:

Those files are 100% valid in any web browser, new or old. We’ve quite literally just made a website.

The Sheet is Linked Up to the HTML

We do need to connect the HTML and CSS though. As in make sure the styles we wrote in our sheet get loaded onto the web page.

A webpage without CSS is pretty barebones:

See the Pen Style-less Webpage by Geoff Graham (@geoffgraham) on CodePen.

Once we link up the CSS file, voila!

See the Pen Webpage With Styles by Geoff Graham (@geoffgraham) on CodePen.

How did that happen? if you look at the top of any webpage, there’s going to be a <head> tag that contains information about the HTML document:

<!DOCTYPE html>
<html> <head> <!-- a bunch of other stuff --> </head> <body> <!-- the page content --> </body> </html>

Even though the code inside the <head> might look odd, there is typically one line (or more, if we’re using multiple stylesheets) that references the sheet. It looks something like this:

<head> <link rel="stylesheet" type="text/css" href="styles.css" />
</head>

This line tells the web browser as it reads this HTML file:

  1. I’d like to link up a style sheet
  2. Here’s where it is located

You can name the sheet whatever you want:

  • styles.css
  • global.css
  • seriously-whatever-you-want.css

The important thing is to give the correct location of the CSS file, whether that’s on your web server, a The Sheet is Not Required for HTML
You saw the example of a barebones web page above. No web page is required to use a stylesheet.
Also, we can technically write CSS directly in the HTML using the HTML style attribute. This is called inline styling and it goes a little something like this if you imagine you’re looking at the code of an HTML file:
<h1 style=”font-size: 24px; line-height: 36px; color: #333333″>A Headline</h1>
<p style=”font-size: 16px; line-height: 24px; color: #000000;”>Some paragraph content.</p>
<!– and so on –>
While that’s possible, there are three serious strikes against writing styles this way: If you decide to use a stylesheet later, it is extremely difficult to override inline styles with the styles in the HTML. Inline styles take priority over styles in a sheet.
Maintaining all of those styles is tough if you need to make a “quick” change and it makes the HTML hard to read.
There’s something weird about saying we’re writing CSS inline when there really is no cascade or sheet. All we’re really writing are styles. There is a second way to write CSS in the HTML and that’s directly in the <head> in a <style> block:
<head> <style> h1 { color: #333; font-size: 24px; line-height: 36px; } p { color: #000; font-size: 16px; line-height: 24px; } </style>
</head>
That does indeed make the HTML easier to read, already making it better than inline styling. Still, it’s hard to manage all styles this way because it has to be managed on each and every webpage of a site, meaning one “quick” change might have to be done several times, depending on how many pages we’re dealing with.
An external sheet that can be called once in the <head> is usually your best bet.
The Sheet is Important
I hope that you’re starting to see the importance of the sheet by this point. It’s a core part of writing CSS. Without it, styles would be difficult to manage, HTML would get cluttered, and the cascade would be nonexistent in at least one case.
The sheet is the core component of CSS. Sure, it often appears to play second fiddle to the first “S” but perhaps that’s because we all have an quiet understanding of its importance.
Leveling Up
Now that you’re equipped with information about stylesheets, here are more resources you jump into to get a deeper understanding for how CSS behaves: Specifics on Specificity – The cascade is a confusing concept and this article breaks down the concept of specificity, which is a method for how to manage it.

  • The latest ways to deal with the cascade, inheritance and specificity – That’s a lot of words, but the this article provides pro tips on how to manage the cascade, including some ideas that may be possible in the future.
  • Override Inline Styles with CSS – This is an oldie, but goodie. While the technique is probably not best practice today, it’s a good illustration of how to override those inline styles we mentioned earlier.
  • When Using !important is The Right Choice – This article is a perfect call-and-response to the previous article about why that method may not be best practice.

  • CSS Basics: The Second “S” in CSS is a post from CSS-Tricks

    Direction Aware Hover Effects

    This is a particular design trick that never fails to catch people’s eye! I don’t know the exact history of who-thought-of-what first and all that, but I know I have seen a number of implementations of it over the years. I figured I’d round a few of them up here.

    Noel Delagado

    See the Pen Direction-aware 3D hover effect (Concept) by Noel Delgado (@noeldelgado) on CodePen.

    The detection here is done by tracking the mouse position on mouseover and mouseout and calculating which side was crossed. It’s a small amount of clever JavaScript, the meat of which is figuring out that direction:

    var getDirection = function (ev, obj) { var w = obj.offsetWidth, h = obj.offsetHeight, x = (ev.pageX - obj.offsetLeft - (w / 2) * (w > h ? (h / w) : 1)), y = (ev.pageY - obj.offsetTop - (h / 2) * (h > w ? (w / h) : 1)), d = Math.round( Math.atan2(y, x) / 1.57079633 + 5 ) % 4; return d;
    };

    Then class names are applied depending on that direction to trigger the directional CSS animations.

    Fabrice Weinberg

    See the Pen Direction aware hover pure CSS by Fabrice Weinberg (@FWeinb) on CodePen.

    Fabrice uses just pure CSS here. They don’t detect the outgoing direction, but they do detect the incoming direction by way of four hidden hoverable boxes, each rotated to cover a triangle. Like this:

    Codrops

    Demo

    In an article by Mary Lou on Codrops from 2012, Direction-Aware Hover Effect with CSS3 and jQuery, the detection is also done in JavaScript. Here’s that part of the plugin:

    _getDir: function (coordinates) { // the width and height of the current div var w = this.$el.width(), h = this.$el.height(), // calculate the x and y to get an angle to the center of the div from that x and y. // gets the x value relative to the center of the DIV and "normalize" it x = (coordinates.x - this.$el.offset().left - (w / 2)) * (w > h ? (h / w) : 1), y = (coordinates.y - this.$el.offset().top - (h / 2)) * (h > w ? (w / h) : 1), // the angle and the direction from where the mouse came in/went out clockwise (TRBL=0123); // first calculate the angle of the point, // add 180 deg to get rid of the negative values // divide by 90 to get the quadrant // add 3 and do a modulo by 4 to shift the quadrants to a proper clockwise TRBL (top/right/bottom/left) **/ direction = Math.round((((Math.atan2(y, x) * (180 / Math.PI)) + 180) / 90) + 3) % 4; return direction;
    },

    It’s technically CSS doing the animation though, as inline styles are applied as needed to the elements.

    John Stewart

    See the Pen Direction Aware Hover Goodness by John Stewart (@johnstew) on CodePen.

    John leaned on Greensock to do all the detection and animation work here. Like all the examples, it has its own homegrown geometric math to calculate the direction in which the elements were hovered.

    // Detect Closest Edge
    function closestEdge(x,y,w,h) { var topEdgeDist = distMetric(x,y,w/2,0); var bottomEdgeDist = distMetric(x,y,w/2,h); var leftEdgeDist = distMetric(x,y,0,h/2); var rightEdgeDist = distMetric(x,y,w,h/2); var min = Math.min(topEdgeDist,bottomEdgeDist,leftEdgeDist,rightEdgeDist); switch (min) { case leftEdgeDist: return "left"; case rightEdgeDist: return "right"; case topEdgeDist: return "top"; case bottomEdgeDist: return "bottom"; }
    } // Distance Formula
    function distMetric(x,y,x2,y2) { var xDiff = x - x2; var yDiff = y - y2; return (xDiff * xDiff) + (yDiff * yDiff);
    }

    Gabrielle Wee

    See the Pen CSS-Only Direction-Aware Cube Links by Gabrielle Wee ✨ (@gabriellewee) on CodePen.

    Gabrielle gets it done entirely in CSS by positioning four hoverable child elements which trigger the animation on a sibling element (the cube) depending on which one was hovered. There is some tricky stuff here involving clip-path and transforms that I admit I don’t fully understand. The hoverable areas don’t appear to be triangular like you might expect, but rectangles covering half the area. It seems like they would overlap ineffectively, but they don’t seem to. I think it might be that they hang off the edges slightly giving a hover area that allows each edge full edge coverage.

    Elmer Balbin

    See the Pen Direction Aware Tiles using clip-path Pure CSS by Elmer Balbin (@elmzarnsi) on CodePen.

    Elmer is also using clip-path here, but the four hoverable elements are clipped into triangles. You can see how each of them has a point at 50% 50%, the center of the square, and has two other corner points.

    clip-path: polygon(0 0, 100% 0, 50% 50%)
    clip-path: polygon(100% 0, 100% 100%, 50% 50%);
    clip-path: polygon(0 100%, 50% 50%, 100% 100%);
    clip-path: polygon(0 0, 50% 50%, 0 100%);

    Nigel O Toole

    Demo

    Raw JavaScript powers Nigel’s demo here, which is all modernized to work with npm and modules and all that. It’s familiar calculations though:

    const _getDirection = function (e, item) { // Width and height of current item let w = item.offsetWidth; let h = item.offsetHeight; let position = _getPosition(item); // Calculate the x/y value of the pointer entering/exiting, relative to the center of the item. let x = (e.pageX - position.x - (w / 2) * (w > h ? (h / w) : 1)); let y = (e.pageY - position.y - (h / 2) * (h > w ? (w / h) : 1)); // Calculate the angle the pointer entered/exited and convert to clockwise format (top/right/bottom/left = 0/1/2/3). See https://stackoverflow.com/a/3647634 for a full explanation. let d = Math.round(Math.atan2(y, x) / 1.57079633 + 5) % 4; // console.table([x, y, w, h, e.pageX, e.pageY, item.offsetLeft, item.offsetTop, position.x, position.y]); return d;
    };

    The JavaScript ultimately applies classes, which are animated in CSS based on some fancy Sass-generated animations.

    Giana

    A CSS-only take that handles the outgoing direction nicely!

    See the Pen CSS-only directionally aware hover by Giana (@giana) on CodePen.


    Seen any others out there? Ever used this on something you’ve built?


    Direction Aware Hover Effects is a post from CSS-Tricks

    Offline *Only* Viewing

    It made the rounds a while back that Chris Bolin built a page of his personal website that could only be viewed while you are offline.

    This page itself is an experiment in that vein: What if certain content required us to disconnect? What if readers had access to that glorious focus that makes devouring a novel for hours at a time so satisfying? What if creators could pair that with the power of modern devices? Our phones and laptops are amazing platforms for inventive content—if only we could harness our own attention.

    Now Bolin has a whole magazine around this same concept called The Disconnect!

    The Disconnect is an offline-only, digital magazine of commentary, fiction, and poetry. Each issue forces you to disconnect from the internet, giving you a break from constant distractions and relentless advertisements.

    I believe it’s some Service Worker trickery to serve different files depending on the state of the network. Usually, Service Workers are meant to serve cached files when the network is off or slow such as to make the website continue to work. This flips that logic on its head, preventing files from being served until the network is off.


    Offline *Only* Viewing is a post from CSS-Tricks

    Using Default Parameters in ES6

    I’ve recently begun doing more research into what’s new in JavaScript, catching up on a lot of the new features and syntax improvements that have been included in ES6 (i.e. ES2015 and later).

    You’ve likely heard about and started using the usual stuff: arrow functions, let and const, rest and spread operators, and so on. One feature, however, that caught my attention is the use of default parameters in functions, which is now an official ES6+ feature. This is the ability to have your functions initialize parameters with default values even if the function call doesn’t include them.

    The feature itself is pretty straightforward in its simplest form, but there are quite a few subtleties and gotchas that you’ll want to note, which I’ll try to make clear in this post with some code examples and demos.

    Default Parameters in ES5 and Earlier

    A function that automatically provides default values for undeclared parameters can be a beneficial safeguard for your programs, and this is nothing new.

    Prior to ES6, you may have seen or used a pattern like this one:

    function getInfo (name, year, color) { year = (typeof year !== 'undefined') ? year : 2018; color = (typeof color !== 'undefined') ? color : 'Blue'; // remainder of the function...
    }

    In this instance, the getInfo() function has only one mandatory parameter: name. The year and color parameters are optional, so if they’re not provided as arguments when getInfo() is called, they’ll be assigned default values:

    getInfo('Chevy', 1957, 'Green');
    getInfo('Benz', 1965); // default for color is "Blue"
    getInfo('Honda'); // defaults are 2018 and "Blue"

    Try it on CodePen

    Without this kind of check and safeguard in place, any uninitiated parameters would default to a value of undefined, which is usually not desired.

    You could also use a truthy/falsy pattern to check for parameters that don’t have values:

    function getInfo (name, year, color) { year = year || 2018; color = color || 'Blue'; // remainder of the function...
    }

    But this may cause problems in some cases. In the above example, if you pass in a value of “0” for the year, the default 2018 will override it because 0 evaluates as falsy. In this specific example, it’s unlikely you’d be concerned about that, but there are many cases where your app might want to accept a value of 0 as a valid number rather than a falsy value.

    Try it on CodePen

    Of course, even with the typeof pattern, you may have to do further checks to have a truly bulletproof solution. For example, you might expect an optional callback function as a parameter. In that case, checking against undefined alone wouldn’t suffice. You’d also have to check if the passed-in value is a valid function.

    So that’s a bit of a summary covering how we handled default parameters prior to ES6. Let’s look at a much better way.

    Default Parameters in ES6

    If your app requires that you use pre-ES6 features for legacy reasons or because of browser support, then you might have to do something similar to what I’ve described above. But ES6 has made this much easier. Here’s how to define default parameter values in ES6 and beyond:

    function getInfo (name, year = 2018, color = 'blue') { // function body here...
    }

    Try it on CodePen

    It’s that simple.

    If year and color values are passed into the function call, the values passed in as arguments will supersede the ones defined as parameters in the function definition. This works exactly the same way as with the ES5 patterns, but without all that extra code. Much easier to maintain, and much easier to read.

    This feature can be used for any of the parameters in the function head, so you could set a default for the first parameter along with two other expected values that don’t have defaults:

    function getInfo (name = 'Pat', year, color) { // function body here...
    }

    Dealing With Omitted Values

    Note that—in a case like the one above—if you wanted to omit the optional name argument (thus using the default) while including a year and color, you’d have to pass in undefined as a placeholder for the first argument:

    getInfo(undefined, 1995, 'Orange');

    If you don’t do this, then logically the first value will always be assumed to be name.

    The same would apply if you wanted to omit the year argument (the second one) while including the other two (assuming, of course, the second parameter is optional):

    getInfo('Charlie', undefined, 'Pink');

    I should also note that the following may produce unexpected results:

    function getInfo (name, year = 1965, color = 'blue') { console.log(year); // null
    }
    getInfo('Frankie', null, 'Purple');

    Try it on CodePen

    In this case, I’ve passed in the second argument as null, which might lead some to believe the year value inside the function should be 1965, which is the default. But this doesn’t happen, because null is considered a valid value. And this makes sense because, according to the spec, null is viewed by the JavaScript engine as the intentional absence of an object’s value, whereas undefined is viewed as something that happens incidentally (e.g. when a function doesn’t have a return value it returns undefined).

    So make sure to use undefined and not null when you want the default value to be used. Of course, there might be cases where you want to use null and then deal with the null value within the function body, but you should be familiar with this distinction.

    Default Parameter Values and the arguments Object

    Another point worth mentioning here is in relation to the arguments object. The arguments object is an array-like object, accessible inside a function’s body, that represents the arguments passed to a function.

    In non-strict mode, the arguments object reflects any changes made to the argument values inside the function body. For example:

    function getInfo (name, year, color) { console.log(arguments); /* [object Arguments] { 0: "Frankie", 1: 1987, 2: "Red" } */ name = 'Jimmie'; year = 1995; color = 'Orange'; console.log(arguments); /* [object Arguments] { 0: "Jimmie", 1: 1987, 2: "Red" } */
    } getInfo('Frankie', 1987, 'Red');

    Try it on CodePen

    Notice in the above example, if I change the values of the function’s parameters, those changes are reflected in the arguments object. This feature was viewed as more problematic than beneficial, so in strict mode the behavior is different:

    function getInfo (name, year, color) { 'use strict'; name = 'Jimmie'; year = 1995; color = 'Orange'; console.log(arguments); /* [object Arguments] { 0: "Frankie", 1: 1987, 2: "Red" } */
    } getInfo('Frankie', 1987, 'Red');

    Try it on CodePen

    As shown in the demo, in strict mode the arguments object retains its original values for the parameters.

    That brings us to the use of default parameters. How does the arguments object behave when the default parameters feature is used? Take a look at the following code:

    function getInfo (name, year = 1992, color = 'Blue') { console.log(arguments.length); // 1 console.log(year, color); // 1992 // "Blue" year = 1995; color = 'Orange'; console.log(arguments.length); // Still 1 console.log(arguments); /* [object Arguments] { 0: "Frankie" } */ console.log(year, color); // 1995 // "Orange"
    } getInfo('Frankie');

    Try it on CodePen

    There are a few things to note in this example.

    First, the inclusion of default parameters doesn’t change the arguments object. So, as in this case, if I pass only one argument in the functional call, the arguments object will hold a single item—even with the default parameters present for the optional arguments.

    Second, when default parameters are present, the arguments object will always behave the same way in strict mode and non-strict mode. The above example is in non-strict mode, which usually allows the arguments object to be modified. But this doesn’t happen. As you can see, the length of arguments remains the same after modifying the values. Also, when the object itself is logged, the name value is the only one present.

    Expressions as Default Parameters

    The default parameters feature is not limited to static values but can include an expression to be evaluated to determine the default value. Here’s an example to demonstrate a few things that are possible:

    function getAmount() { return 100;
    } function getInfo (name, amount = getAmount(), color = name) { console.log(name, amount, color)
    } getInfo('Scarlet');
    // "Scarlet"
    // 100
    // "Scarlet" getInfo('Scarlet', 200);
    // "Scarlet"
    // 200
    // "Scarlet" getInfo('Scarlet', 200, 'Pink');
    // "Scarlet"
    // 200
    // "Pink"

    Try it on CodePen

    There are a few things to take note of in the code above. First, I’m allowing the second parameter, when it’s not included in the function call, to be evaluated by means of the getAmount() function. This function will be called only if a second argument is not passed in. This is evident in the second getInfo() call and the subsequent log.

    The next key point is that I can use a previous parameter as the default for another parameter. I’m not entirely sure how useful this would be, but it’s good to know it’s possible. As you can see in the above code, the getInfo() function sets the third parameter (color) to equal the first parameter’s value (name), if the third parameter is not included.

    And of course, since it’s possible to use functions to determine default parameters, you can also pass an existing parameter into a function used as a later parameter, as in the following example:

    function getFullPrice(price) { return (price * 1.13);
    } function getValue (price, pricePlusTax = getFullPrice(price)) { console.log(price.toFixed(2), pricePlusTax.toFixed(2))
    } getValue(25);
    // "25.00"
    // "28.25" getValue(25, 30);
    // "25.00"
    // "28.25"

    Try it on CodePen

    In the above example, I’m doing a rudimentary tax calculation in the getFullPrice() function. When this function is called, it uses the existing price parameter as part of the pricePlusTax evaluation. As mentioned earlier, the getFullPrice() function is not called if a second argument is passed into getValue() (as demonstrated in the second getValue() call).

    Two things to keep in mind with regards to the above. First, the function call in the default parameter expression needs to include the parentheses, otherwise you’ll receive a function reference rather than an evaluation of the function call.

    Second, you can only reference previous parameters with default parameters. In other words, you can’t reference the second parameter as an argument in a function to determine the default of the first parameter:

    // this won't work
    function getValue (pricePlusTax = getFullPrice(price), price) { console.log(price.toFixed(2), pricePlusTax.toFixed(2))
    } getValue(25); // throws an error

    Try it on CodePen

    Similarly, as you would expect, you can’t access a variable defined inside the function body from a function parameter.

    Conclusion

    That should cover just about everything you’ll need to know to get the most out of using default parameters in your functions in ES6 and above. The feature itself is quite easy to use in its simplest form but, as I’ve discussed here, there are quite a few details worth understanding.

    If you’d like to read more on this topic, here are some sources:

    • Understanding ECMAScript 6 by Nicholas Zakas. This was my primary source for this article. Nicholas is definitely my favorite JavaScript author.
    • Arguments object on MDN
    • Default Parameters on MDN

    Using Default Parameters in ES6 is a post from CSS-Tricks

    Fallbacks for Videos-as-Images

    Safari 11.1 shipped a strange-but-very-useful feature: the ability to use a video source in the <img> tag. The idea is it does the same job as a GIF (silent, autoplaying, repeating), but with big performance gains. How big? “20x faster and decode 7x faster than the GIF equivalent,” says Colin Bendell.

    Not all browsers support this so, to do a fallback, the <picture> element is ready. Bruce Lawson shows how easy it can be:

    <picture> <source type="video/mp4" srcset="adorable-cat.mp4"> <!-- perhaps even an animated WebP fallback here as well --> <img src="adorable-cat.gif" alt="adorable cat tears throat out of owner and eats his eyeballs">
    </picture>

    Šime Vidas notes you get wider browser support by using the <video> tag:

    <video src="https://media.giphy.com/media/klIaoXlnH9TMY/giphy.mp4" muted autoplay loop playsinline></video>

    But as Bendell noted, the performance benefits aren’t there with video, notably the fact that video isn’t helped out by the preloader. Sadly, <video> it is for now, as:

    there is this nasty WebKit bug in Safari that causes the preloader to download the first <source> regardless of the mimetype declaration. The main DOM loader realizes the error and selects the correct one. However, the damage will be done. The preloader squanders its opportunity to download the image early and on top of that, downloads the wrong version wasting bytes. The good news is that I’ve patched this bug and it should land in Safari TP 45.

    In short, using the <picture> and <source type> for mime-type selection is not advisable until the next version of Safari reaches the 90%+ of the user base.

    Still, eventually, it’ll be quite useful.


    Fallbacks for Videos-as-Images is a post from CSS-Tricks

    A Short History of WaSP and Why Web Standards Matter

    In August of 2013, Aaron Gustafson posted to the WaSP blog. He had a bittersweet message for a community that he had helped lead:

    Thanks to the hard work of countless WaSP members and supporters (like you), Tim Berners-Lee’s vision of the web as an open, accessible, and universal community is largely the reality. While there is still work to be done, the sting of the WaSP is no longer necessary. And so it is time for us to close down The Web Standards Project.

    If there’s just the slightest hint of wistful regret in Gustafson’s message, it’s because the Web Standards Project changed everything that had become the norm on the web during its 15+ years of service. Through dedication and developer advocacy, they hoisted the web up from a nest of browser incompatibility and meaningless markup to the standardized and feature-rich application platform most of us know today.

    I previously covered what it took to bring CSS to the World Wide Web. This is the other side of that story. It was only through the efforts of many volunteers working tirelessly behind the scenes that CSS ever had a chance to become what it is today. They are the reason we have web standards at all.

    Introducing Web Standards

    Web standards weren’t even a thing in 1998. There were HTML and CSS specifications and drafts of recommendations that were managed by the W3C, but they had spotty and uneven browser support which made them little more than words on a page. At the time, web designers stood at the precipice of what would soon be known as the Browser Wars, where Netscape and Microsoft raced to implement exclusive features and add-ons in an escalating fight for market share. Rather than stick to any official specification, these browsers forced designers to support either Netscape Navigator or Internet Explorer. And designers were definitely not happy about it.

    Supporting both browsers and their competing feature implementations was possible, but it was also difficult and unreliable, like building a house on sand. To help each other along, many developers began joining mailing lists to swap tips and hacks for dealing with sites that needed to look good no matter where it was rendered.

    From these mailing lists, a group began to form around an entirely new idea. The problem, this new group realized, wasn’t with the code, but with the browsers that refused to adhere to the codified, open specifications passed down by the W3C. Browsers touted new presentational HTML elements like the <blink> tag, but they were proprietary and provided no layout options. What the web needed was browsers that could follow the standards of the web.

    The group decided they needed to step up and push browsers in the right direction. They called themselves the Web Standards Project. And, since the process would require a bit of a sting, they went by WaSP for short.

    Launching the Web Standards Project

    In August of 1998, WaSP announced their mission to the public on a brand new website: to “support these core standards and encourage browser makers to do the same, thereby ensuring simple, affordable access to Web technologies for all.” Within a few hours, 450 people joined WaSP. In a few months, that number would jump to thousands.

    WaSP took what was basically a two-pronged approach. The first was in public, tapping into the groundswell of developer support they had gathered to lobby for better standards support in browsers. Using grassroots tactics and targeted outreach, WaSP would often send its members on “missions” such as sending emails to browsers explaining in great detail their troubles working with a lack of consistent web standards support.

    They also published scathing reports that put browsers on blast, highlighting all the ways that Netscape or Internet Explorer failed to add necessary support, even go so far to encourage users to use alternative browsers. It was these reports where the project truly lived up to its acronym. One needs to look no further then a quote from WaSP’s savage takedown of Internet Explorer as an example of its ability to sting:

    Quit before the job’s done, and the flamethrower’s the only answer. Because that’s our job. We speak for thousands of Web developers, and through them, millions of Web users.

    The second prong of WaSP’s approach included privately reaching out to passionate developers on browser teams. The problem, for big companies like Netscape and Microsoft, wasn’t that engineers were against web standards. Quite the contrary, actually. Many browser engineers believed deeply in WaSP’s mission but were resisted by perceived business interests and red-tape bureaucracy time and time again. As a result, WaSP would often work with browser developers to find the best path forward and advocate on their behalf to the higher-ups when necessary.

    Holding it All Together

    To help WaSP navigate its way through its missions, reports, and outreach, a Steering Committee was formed. This committee helped set the project’s goals and reached out to the community to gather support. They were the heralds of a better day soon to come, and more than a few influential members would pass through their ranks before the project was over, including: Rachel Cox, Tim Bray, Steve Champeon, Glenn Davis, Glenda Sims, Todd Fahrner, Molly Holzschalg and Aaron Gustafson, among many, many others.

    At the top of it all was a project lead who set the tone for the group and gave developers a unified voice. The position was initially held by George Olsen, one of the founders of the project, but was soon picked up by another founding member: Jeffrey Zeldman.

    A network of loosely connected satellite groups orbiting around the Steering Committee helped developers and browsers alike understand the importance of web standards. There was, for instance, an Accessibility group that bridged the W3C with browser makers to ensure the web was open and accessible to everyone. Then there was the CSS Samurai, who published reports about CSS support (or, more commonly, lack thereof) in different browsers. They were the ones that devised the Box Acid test and offered guidance to browsers as they worked to expand CSS support. Todd Fahrner, who helped save CSS with doctype switching, counted himself among the CSS Samurai.

    Making an Impact

    WaSP was huge and growing all the time. Its members were passionate and, little by little, clusters of the community came together to enact change. And that is exactly what happened.

    The changes felt kind of small at first but soon they bordered on massive. When Netscape was kicking around the idea of a new rendering engine named Gecko that would include much better standards support across the board, their initial timeline would have taken months to release. But the WaSP swarmed, emailing and reaching out to Netscape to put pressure on them to release Gecko sooner. It worked and, by the next release, Gecko (and better web standards) shipped.

    Tantek Çelik was another member of WaSP. The community inspired him to take a stand on web standards at his day job as lead developer of Internet Explorer for Mac. It was through the encouragement and support of WaSP that he and his team released version 5 with full CSS Level 1 support.

    Internet Explorer 5 for Mac was released with full CSS Level 1 support

    In August of 2001, after years of public reports and private outreach and developer advocacy, the WaSP sting provoked seismic change in Internet Explorer as version 6 released with CSS Level 1 support and the latest HTML features. The upgrades were due in no small part to the work at the Web Standards Project and their work with dedicated members of the browser team. It appeared that standards were beginning to actually win out. The WaSP’s mission may have even been over.

    But instead of calling it quits, they shifted tactics a bit.

    Teaching Standards to a New Generation

    In the early 2000’s, WaSP would radically change its approach to education and developer outreach.

    They started with the launch of the Browser Upgrade Campaign which educated users who were coming online for the very first time and knew absolutely nothing about web standards and modern browsers. Site owners were encouraged to add some JavaScript and a banner to their sites to target these users. As a result, those surfing to a site on older versions of standards-compliant browsers, like Firefox or Opera, were greeted by a banner simply directing them to upgrade. Users visiting the site on a really old browser, like pre-IE5 or Netscape 5, would redirect visitors to an entirely new page explaining why upgrading to a modern browser with standards support was in their best interest.

    A page from the Browser Upgrade Campaign

    WaSP was going to bring the web up to speed, even if they had to do it one person at a time. Perhaps no one articulated this sentiment better than Molly Holzschalg when she wrote “Raise Your Standards” in February 2002. In the article, she broke down what web standards are and what they meant for developers and designers. She celebrated the work that had been done by browsers and the community working to make web standards a thing in the first place.

    But, she argued, the web was far from done. It was now time for developers to step up to the plate and assume the responsibility for standards themselves by coding it into all of their sites. She wrote:

    The Consortium is fraught with its own internal issues, and its actions—while almost always in the best interests of professional Web authors—are occasionally politicized.

    Therefore, as Web authors, we’re personally responsible for making implementation decisions within the framework of a site’s markup needs. It’s our job to administer recommendations to the best of our abilities.

    This, however, would not be easy. It would once again require the combined efforts of WaSP members to pull together and teach the web a new way to code. Some began publishing tutorials to their personal blogs or on A List Apart. Others created a standards-based online curriculum for web developers who were new to the field. A few members even formed brand-new task forces to work with popular software tools, like Adobe Dreamweaver, and ensure that standards were supported there as well.

    The redesigns of ESPN and Wired, which stood as a testament and example for standards-based designs for years to come, were undertaken in part because members of those teams were inspired by the work that WaSP was doing. They would not have been able to take those crucial first steps if not for the examples and tutorials made freely available to them by gracious WaSP members.

    That is why web standards is basically second nature to many web developers today. It’s also why we have such a free spirit of creative exchange in our industry. It all started when WaSP decided to share the correct way of doing things right out in the open.

    Looking Past Web Standards

    It was this openness that carried WaSP into the late 2010’s. When Holzschlag took over as lead, she advocated for transparency and collaboration between browser makers and the web community. The WaSP, Holzschlag realized, was no longer necessary and could be done from within. For example, she made inroads at Microsoft to help make web standards a top priority on their browser team.

    With each subsequent release, browsers began to catch up to the latest standards from the W3C. Browsers like Opera and Firefox actually competed on supporting the latest standards. Google Chrome used web standards as a selling point when it was initially released around the same time. The decade-and-a-half of work by WaSP was paying off. Browser makers were listening to the W3C and the web community, even going so far as to experiment with new standards before they were officially published for recommendation.

    In 2013, WaSP posted its farewell announcement and closed up shop for good. It was a difficult decision for those who had fought long and hard for a better, more accessible and more open web, but it was necessary. There are still a number of battlegrounds for the open web but, thanks to the efforts of WaSP, the one for web standards has been won.

    Enjoy learning about web history? Jay Hoffmann has a weekly newsletter called The History of the Web you can sign up for here.


    A Short History of WaSP and Why Web Standards Matter is a post from CSS-Tricks

    Counting With CSS Counters and CSS Grid

    You’ve heard of CSS Grid, I’m sure of that. It would be hard to miss it considering that the whole front-end developer universe has been raving about it for the past year.

    Whether you’re new to Grid or have already spent some time with it, we should start this post with a short definition directly from the words of W3C:

    Grid Layout is a new layout model for CSS that has powerful abilities to control the sizing and positioning of boxes and their contents. Unlike Flexible Box Layout, which is single-axis–oriented, Grid Layout is optimized for 2-dimensional layouts: those in which alignment of content is desired in both dimensions.

    In my own words, CSS Grid is a mesh of invisible horizontal and vertical lines. We arrange elements in the spaces between those lines to create a desired layout. An easier, stable, and standardized way to structure contents in a web page.

    Besides the graph paper foundation, CSS Grid also provides the advantage of a layout model that’s source order independent: irrespective of where a grid item is placed in the source code, it can be positioned anywhere in the grid across both the axes on screen. This is very important, not only for when you’d find it troublesome to update HTML while rearranging elements on page but also at times when you’d find certain source placements being restrictive to layouts.

    Although we can always move an element to the desired coordinate on screen using other techniques like translate, position, or margin, they’re both harder to code and to update for situations like building a responsive design, compared to true layout mechanisms like CSS Grid.

    In this post, we’re going to demonstrate how we can use the source order independence of CSS Grid to solve a layout issue that’s the result of a source order constraint. Specifically, we’re going to look at checkboxes and CSS Counters.

    Counting With Checkboxes

    If you’ve never used CSS Counters, don’t worry, the concept is pretty simple! We set a counter to count a set of elements at the same DOM level. That counter is incremented in the CSS rules of those individual elements, essentially counting them.

    Here’s the code to count checked and unchecked checkboxes:

    <input type="checkbox">Checkbox #1<br>
    <input type="checkbox">Checkbox #2
    <!-- more checkboxes, if we want them --> <div class="total"> <span class="totalChecked"> Total Checked: </span><br> <span class="totalUnChecked"> Total Unchecked: </span>
    </div>
    ::root { counter-reset: checked-sum, unchecked-sum;
    } input[type="checkbox"] { counter-increment: unchecked-sum;
    } input[type="checkbox"]:checked { counter-increment: checked-sum;
    } .totalUnChecked::after { content: counter(unchecked-sum);
    } .totalChecked::after { content: counter(checked-sum);
    }

    In the above code, two counters are set at the root element using the counter-reset property and are incremented at their respective rules, one for checked and the other for unchecked checkboxes, using counter-increment. The values of the counters are then shown as contents of two empty <span>s’ pseudo elements using counter().

    Here’s a stripped-down version of what we get with this code:

    See the Pen CSS Counter Grid by CSS-Tricks (@css-tricks) on CodePen.

    This is pretty cool. We can use it in to-do lists, email inbox interfaces, survey forms, or anywhere where users toggle boxes and will appreciate being shown how many items are checked and how many are unselected. All this with just CSS! Useful, isn’t it?

    But the effectiveness of counter() wanes when we realize that an element displaying the total count can only appear after all the elements to be counted in the source code. This is because the browser first needs the chance to count all the elements, before showing the total. Hence, we can’t simply change the markup to place the counters above the checkboxes like this:

    <!-- This will not work! -->
    <div class="total"> <span class="totalChecked"> Total Checked: </span><br> <span class="totalUnChecked"> Total Unchecked: </span>
    </div>
    <input type="checkbox">Checkbox #1<br>
    <input type="checkbox">Checkbox #2

    Then, how else can we get the counters above the checkboxes in our layout? This is where CSS Grid and its layout-rendering powers come into play.

    Adding Grid

    We’re basically wrapping the previous HTML in a new <div> element that’ll serve as the grid container:

    <div class="grid"> <input type=checkbox id="c-1"> <label for="c-1">checkbox #1</label> <input type=checkbox id="c-2"> <label for="c-2">checkbox #2</label> <input type=checkbox id="c-3"> <label for="c-3">checkbox #3</label> <input type=checkbox id="c-4"> <label for="c-4">checkbox #4</label> <input type=checkbox id="c-5"> <label for="c-5">checkbox #5</label> <input type=checkbox id="c-6"> <label for="c-6">checkbox #6</label> <div class=total> <span class="totalChecked"> Total Checked: </span> <span class="totalUnChecked"> Total Unchecked: </span> </div> </div>

    And, here is the CSS for our grid:

    .grid { display: grid; /* creates the grid */ grid-template-columns: repeat(2, max-content); /* creates two columns on the grid that are sized based on the content they contain */
    } .total { grid-row: 1; /* places the counters on the first row */ grid-column: 1 / 3; /* ensures the counters span the full grid width, forcing other content below */
    }

    This is what we get as a result (with some additional styling):

    See the Pen CSS Counter Grid by Preethi (@rpsthecoder) on CodePen.

    See that? The counters are now located above the checkboxes!

    We defined two columns on the grid element in the CSS, each accommodating its own content to their maximum size.

    When we grid-ify an element, its contents (text including) block-ify, meaning they acquire a grid-level box (similar to block-level box) and are automatically placed in the available grid cells.

    In the demo above, the counters take up both the grid cells in the first row as specified, and following that, every checkbox resides in the first column and the text after each checkbox stays in the last column.

    The checkboxes are forced below the counters without changing the actual source order!

    Since we didn’t change the source order, the counter works and we can see the running total count of checked and unchecked checkboxes at the top the same way we did when they were at the bottom. The functionality is left unaffected!

    To be honest, there’s a staggering number of ways to code and implement a CSS Grid. You can use grid line numbers, named grid areas, among many other methods. The more you know about them, the easier it gets and the more useful they become. What we covered here is just the tip of the iceberg and you may find other approaches to create a grid that work equally well (or better).


    Counting With CSS Counters and CSS Grid is a post from CSS-Tricks