This is only one example of dynamic CSS there are virtually limitless possibilities when combining CSS and server-side code. This would set the background image to whatever was stored in the $user_country variable.

For example (and I absolutely love doing things like this): If this is the case, you can use a server-side scripting language to do so. To facilitate potentially solving your problem given the information you've provided, I'm going to assume you're seeking dynamic CSS. By using something like body, it will execute immediately on page load. In both techniques, the code doesn't execute unless the CSS selector matches an element within the document. The HTC file executes the main() function on the event ondocumentready (referring to the HTC document's readiness.) XBL with Firefoxįirefox supports a similar XML-script-executing hack, using XBL.Īll of the code within the constructor tag will be executed (a good idea to wrap code in a CDATA section.) HTC with IEĪnd within that script.htc file have something like: These techniques don't exectue JavaScript from CSS directly, but the effect is the same.

A similar technique for Firefox exists, using XBL. As Paolo mentions, one way in IE is the expression technique, but there's also the more obscure HTC behavior, in which a seperate XML that contains your script is loaded via CSS. IE and Firefox both contain ways to execute JavaScript from CSS. This can be particularly useful when building large, complex web applications.įor example, instead of having a separate CSS file with styles like this. It also allows for more dynamic styling through the use of JavaScript expressions, which can be computed at runtime. This allows for more modular and reusable styles and better integration with other aspects of the application logic. If you're completely new to CSS-in-JS, here's a general gist of what it does and how it works.ĬSS-in-JS is a method for writing CSS styles in JavaScript files.

Css for js