what is style.css?ver=1 tag?

Question

I found out that some websites use css tag like style.css?ver=1. What is this?

What is purpose of ?ver=1?

How do I do it in code?

Answer 1

If you are developing a web application in HTML and CSS or any other technology, and you are using some external CSS or JS files, you might notice one thing that in some cases if you made any changes to your existing .css or .js files then the browsers are not reflecting the changes immediately.

What happens in that case is that the browser do not download a fresh copy of the latest version of the .css and .js files, instead it uses those files stored in your local cache. As a result the changes you made recently are not visible to you.

The above case when you load the web page the browser will treat "style.css" as a different file along with "?v=1.1". Hence the browser is forced to download a fresh copy if the stylesheet or the script file.