Why does css load faster

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Ask Question. Asked 10 years, 4 months ago.

Active 6 years, 7 months ago. Viewed 35k times. Improve this question. GreatestSwordsman GreatestSwordsman 1, 5 5 gold badges 19 19 silver badges 38 38 bronze badges. Add a comment. Active Oldest Votes. I would worry more about the other aspects though. Having the image as a background-image means: The image is not a content It is not printable You can use a sprite to reduce the number of HTTP requests thus improving performance It is slower to animate background-image than img.

Improve this answer. Almost everything that is asked here can be known by google and "verifying the answers first" — Jawad. Both options are simpler to develop, use less code, can adapt to any screen size, and render faster than floats because the browser can natively determine the optimum layout. The most reliable and fastest code is the code you need never write!

The smaller your stylesheet, the quicker it will download and parse. All developers start with good intentions, but CSS can bloat over time as the feature count increases. A few recommendations to consider:. Typically, randomly generated class names are created at build time so it becomes impossible for components to conflict. For example, you can set default fonts, colors, sizes, tables and form fields that are universally applied to every element in a single place.

There is rarely a need to declare every style in every component. Even the most complex CSS selectors take milliseconds to parse , but reducing complexity will reduce file sizes and aid browser parsing. Do you really need this sort of selector?! Again, be wary of deep nesting in preprocessors such as Sass, where complex selectors can be inadvertently created.

Some properties are slower to render than others. For added jankiness, try placing box shadows on all your elements! Browser performance will vary but, in general, anything which causes a recalculation before painting will be more costly in terms of performance:. Native CSS transitions and animations will always be faster than JavaScript-powered effects that modify the same properties. That said, avoid animation for the sake of it. Subtle effects can enhance the user experience without adversely affecting performance.

Optimizing CSS and JavaScript for the browser involves more than just the removal of new line characters, white space, shortening variable names, combining duplicate CSS, etc. Does that mean we have to go through all of our code and minify it ourselves? Alternatively, the PageSpeed Module , integrates with an Apache or Nginx web server to automatically optimize your site, including resource minification.

Your browser waits for all CSS to be loaded before it can begin rendering a web page. The more CSS you have, the longer it will take for your web page to be styled. When including your styles, the media attribute can be very helpful. By marking it as "print" the browser will not have to wait until it is loaded. Media Queries allow you to load CSS depending on the size of the viewport and in an increasingly mobile age, it is highly recommended you use them.

Based on your query, your browser decides if it has to load the CSS or not. Priorities are important because some resources are critical to render a page eg. Without those browser will not render any pixels on the screen. The reason for this is that styles define the look of the page and rendering page first without them would be a waste of processing powers and bad user experience.

In short no CSS downloaded, no page rendered. As you can see CSS has a huge impact on the load time of your webpage. There are two basic areas affecting webpage load time when we talk about CSS:. If you want to faster load times, making your CSS files smaller is a good idea. I would suggest checking the result code for unnecessary bloat. Especially if you are using PostCSS with multiple plugins. That may seem like a trivial issue with very little effect, but resulting savings were around 3 kB for small stylesheet like mine.

I think that is a great improvement for very little work. And for large CSS it has the potential to have an even bigger impact. All I had to do was to update a browserslist config which is used by Autoprefixer and other similar tools to target generated code for specific browser versions. I have updated my PostCSS config a bit as well.

I also added the plugin to concatenate media queries together to save some extra space. See the PostCSS config in the source code and my browserslist definition if you want to see my exact setup. So we shrank our CSS file, but we still need to download it. We can speed up the webpage load time by reducing network requests.

And best network requests are no requests at all. We can inline our styles directly into the HTML to avoid the need for downloading any external stylesheets and thus saving some time.

Of course, including an entire 9kb stylesheet or large for bigger projects on every page is not very effective.