Inline CSS & JS

The majority of websites on the Internet today have separate HTML, CSS, and JS files.
When things slow down, however, a web developer can look for unique ways to reduce the number of requests for separate files. One method to do this includes using in-line CSS and JavaScript instead of multiple stored files for each one.Inline css & js

In some cases, only certain parts of the CSS or JavaScript get included in the main HTML document. For example, below the HTML title tag, the developer may insert a short in-line style blurb that gives basic specifications about font styles, background color, or alignment. They may still choose to use an external style sheet for more detailed things.

Using in-line JS and CSS minimizes the back-and-forth queries necessary to display the website. However, it does make the HTML files longer. Also, parts of the code that exists within it will not get saved in the server cache. Ultimately, the call to go external or in-line remains up to the webmaster or development team of a particular website. With many other load time decreasing methods already in use, they may decide this is not worth it.

The best solution to optimize website speed performance is to use CSS inline only for the essential CSS styles in HTML documents.