Combine CSS & JS files

Combine CSS & JS files

Although not every website uses JavaScript, the majority of them that have any unique functions do. Of course, they also have HTML and cascading style sheets (CSS) that tells the content how to display on the page. When website loads in a browser, all of these separate files need to be read, understood, and manifested for the person trying to view the site. Downloading these things individually adds small amounts of time to the overall loading process.

To avoid the type of latency caused by inefficient loading, developers can combine all the separate CSS files together and, likewise, all the separate JavaScript files into one. Make sure to test your site after combining. It may break your website, in that case, just exclude the single file causing the problem. A general rule of web development follows the idea that the more files you have, the slower load time can get, and see more potential for problems and blocks occur. Why having trouble with multiple CSS or JS files when you can easily condense them into fewer?

It all comes down to HTTP requests. If you have multiple CSS or JS files, there are more requests going out to the coded files on the server. Just like it would take you more time to ask three questions to another person, it takes more time for a website to do the same thing.

When it comes to increasing the speed at which a website loads, combining CSS files and JavaScript files is probably one of the simplest things to do. As long as the developer creates clean and efficient code, this should not be a problem.

Despite its simplicity and reported success, some people argue that the introduction of the HTTP/2 protocol makes file combining irrelevant. HTTP/2 has parallelism built in for allowing more than one file download using just a single server request. This negates the possibility of latency caused by multiple requests if you use more than one CSS or JavaScript file. In fact, individual files that contain specific code are delivered more effectively with a CDN or caching when using this newer protocol.