php - How to force a browser to show the latest changes to a CSS file?

Question

I made some changes on a CSS file on a PHP site.

The changes do not show up in any browser I test it on until I hold down the CTRL key and click the browser's REFRESH button.

This means that most users are not going to seem the changes I made.

How can I force browsers to show the changes to CSS files immediately (without renaming the CSS file)?

Answer 1

Add a unique string as query string when linking the stylesheet. Here's an example

<link href="style.css?<?=filemtime("style.css")?>" rel="stylesheet" type="text/css" />