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Since writing about the state of CSS resets in 2018, I’ve had a few people ask what my modified CSS reset looks like. As I mentioned in that article, my reset is more like a base at this point because, in addition to resetting some default browser styles, I also include some utilities that I want in every project. You can view the entire CSS file in my Github repository, which will be kept more up

A few years ago, I wrote about how we can use css to style broken images. The technique leveraged on the fact that any styling to the ::before or ::after pseudo-elements on the <img> element will only be applied if the image doesn’t load. So, we could style those elements and they would only display if the image was broken. Here’s an example of how I’ve styled broken images on this site: There are

All browsers ship with a set of default styles that are applied to every web page in what is called the “user agent stylesheet”. Most of these stylesheets are open source so you can have a look through them: Chromium UA stylesheet - Google Chrome & Opera Mozilla UA stylesheet - Firefox WebKit UA stylesheet - Safari A lot of styles are consistent across all user agent stylesheets. For example, I us

In JavaScript, like any other language, there are several ways to achieve the same result, some being more suited to certain situations than others. One of the first concepts I learned about when learning to code was loops, and it seemed like the answer to almost everything. Although loops are great for a lot of use cases, the JavaScript language has provided a suite of methods that can be used to

Web workers, service workers, and worklets. All of these are what I would call “Javascript Workers”, and although they do have some similarities in how they work, they have very little overlap in what they are used for. Broadly speaking, a worker is a script that runs on a thread separate to the browser’s main thread. If you think about your typical Javascript file that is included in your HTML do

With all the new properties related to CSS Grid Layout, one of the distinctions that always confused me was the difference between the grid-template-* and grid-auto-* properties. Specifically the difference between grid-template-rows/columns and grid-auto-rows/columns. Although I knew they were to do with the explicit and implicit grid systems, at face value they seemed to be doing almost the same

As I frequently mention, every element in the document tree is a rectangular box. Broadly speaking, this "rectangular box" consists of two sections. First we have the actual box, which consists of the border, padding, and margin areas. Second, we have the contents of the box; the content area. With the CSS display property, we can control different things about how this box and its children are dr

While learning CSS Grid Layout, I’ve found that the best way to internalise all the new concepts and terminology is by working on various layouts using them. Recently, I decided to try to recreate the GitHub Contribution graph using CSS Grid Layout, and found it was an interesting challenge. As I always find while working with CSS Grid Layout, I end up with far less CSS than I would have using alm

Less than a month ago, HTML 5.2 became an official W3C Recommendation (REC). When a specification reaches the REC stage, this means that it has received the official endorsement of W3C Members and the Director, and that the W3C officially recommends it’s deployment by user agents, and it’s implementation by web page authors. By the REC stage, anything new should have had at least 2 independent imp

Knowing where to start with accessibility testing can be difficult and overwhelming. In my article on Tools for Developing Accessible Websites, I mentioned 5 tools you can use to get started developing more accessible websites. More recently, I have discovered an incredibly powerful tool - pa11y Introducing pa11y # pa11y, pronounced pally, is a set of free and open source tools that aims to make d

Last week, I ran a twitter poll asking the following question - What would be the amount of space between two sibling divs, where the 1st has a margin-bottom of 10px and 2nd a margin-top of 30px? The result of this poll was that 39% of the 754 people who voted got the correct answer, which was 30px. [CSS Quiz] What would be the amount of space between two sibling divs, where the 1st has a margin-b

One incredibly useful new feature introduced with the CSS Grid Layout Specification is the minmax() function. This function opens the door to us being able to write much more powerful and succinct CSS by allowing us to set, as a value for a grid track, a function including both a minimum and maximum value. The minmax() Function # The minmax() function accepts two parameters, a minimum value and a

When HTML is written incorrectly, nothing much happens. Because of this, it's easy to have invalid, unsemantic, or unaccessible bits in markup without it being obvious. There are many ways we can lint our HTML to discover and fix these issues, for example using the W3C Markup Validation Service. Another thing we can do, which can be more easily integrated into a development workflow, is to use som

In my article on Understanding the Critical Rendering Path, I wrote about the effect JavaScript files have on the Critical Rendering Path. JavaScript is considered a "parser blocking resource". This means that the parsing of the HTML document itself is blocked by JavaScript. When the parser reaches a <script> tag, whether that be internal or external, it stops to fetch (if it is external) and run

In the CSS Grid Layout Specification, a grid is defined as the following - The grid is an intersecting set of horizontal and vertical grid lines that divides the grid container’s space into grid areas, into which grid items (representing the grid container’s content) can be placed Err… what? 🤔 CSS Grid Layout introduces a lot of new concepts; there are 17 new properties to learn, and many more ne

The CSS3 calc() function allows us to perform mathematical operations on property values. Instead of declaring, for example, static pixel values for an element's width, we can use calc() to specify that the width be the result of the addition of two or more numeric values. .foo { width: calc(100px + 50px); } Why calc()? # If you have used CSS pre-processors like SASS, the above example is somethin

When a browser receives the HTML response for a page from the server, there are a lot of steps to be taken before pixels are drawn on the screen. This sequence the browsers needs to run through for the initial paint of the page is called the "Critical Rendering Path". Knowledge of the CRP is incredibly useful for understanding how a site's performance can be improved. There are 6 stages to the CRP

Happy new year! 🎊 With the new year, we have a whole new set of things to learn. Although there are many new features, these are 3 new CSS features I'm most excited about adopting this year. 1. Feature Queries # A while ago, I wrote about Feature Queries being the one CSS feature I really want. Well, now its basically here! It is now supported in every major browser (Opera Mini included) besides

The most basic type of iteration method in JavaScript is the for loop. It takes three expressions; a variable declaration, an expression to be evaluated before each iteration, and an expression to be evaluated at the end of each iteration. For example, this for loop will console.log each item in an array. const array = ['a', 'b', 'c', 'd']; for (let i = 0; i < array.length; i++) { console.log(arra

The most accessible format for any content on the web is plain text. Plain text is incredibly malleable, it can be altered in ways to cater to almost any disability. For users with no visual difficulties, they can simply read the text. If a user has visual impairments, the text can be converted to speech. Even if a user has both visual and auditory difficulties, plain text can be converted to brai

A few months ago, I wrote about how you can use system fonts in the browser using the built-in keywords that work with the font shorthand property (see Using System Fonts in the Browser). These keywords can be useful, but they also have some drawbacks, the main one being that they only work with the shorthand font property. This means that we cannot use it in a list of font families with fallbacks

The nth-child() and nth-of-type() selectors are “structural” pseudo-classes, which are classes that allow us to select elements based on information within the document tree that cannot typically be represented by other simple selectors. In the case of nth-child() and nth-of-type(), the extra information is the element’s position in the document tree in relation to its parent and siblings. Althoug

As I have mentioned before, every element in the document tree is just a rectangular box. Each of these boxes has a background layer that can either be fully transparent, a colour, or an image. This background layer is controlled by 8 CSS properties (plus 1 shorthand property). background-color # The background-color property sets a background colour for the element. It's value can be any accepted

If you have worked with Service Workers, you may have run into some issues with previous Service Workers still being in control of a document, even though the file itself has been updated. The reason for this is to do with some nuances in the lifecycle of the Service Worker; it may be installed and valid, but not yet actually in control of the document. A Service Worker can be in one of the follow