stylesheet linked with question mark and numeric value

Question

I can see this site.com/assets/css/screen.css?954d46d92760d5bf200649149cf28ab453c16e2bwhat is this random alpha numeric vales question mark ? i don't think it's taking some value to use or what is it about ? edit : also on refreshing page the alpha-numeric value is same.

Possible duplicate: http://stackoverflow.com/questions/2634123/what-does-the-question-mark-at-then-end-of-a-css-include-url-do — Sir_Faenor, Jun 10 '15 at 08:17
Its probably a cahebuster. When a server encounters `?anything` it will try to send this to the requested page and wait for a response, that way you are certain to get the most recent file. — somethinghere, Jun 10 '15 at 08:18

score 0 · Accepted Answer · edited May 23 '17 at 10:26

It is for preventing the browser from caching the CSS. When a CSS is requested by some browsers, specifically Internet Explorer, the browser will have a local copy of the CSS.

When a request is given to a server as:

site.com/assets/css/screen.css?skdjhfk
site.com/assets/css/screen.css?5sd4f65
site.com/assets/css/screen.css?w4rtwgf
site.com/assets/css/screen.css?helloWd

The server at site.com sees only:

site.com/assets/css/screen.css

And gives the latest version. But when the HTML page is requesting the browser to fetch the CSS as: site.com/assets/css/screen.css, for the first time, it fetches from the site.com server. There are many possibilities that the content might be changed in the meantime when the next request is sent. So programmers generally add a ?and-some-random-text, which is called Query String. This will force the browser to get a new copy from the server.

Some more detailed explanation:

It is a well known problem that IE caches too much of html, even when giving a Cache-Control: no-cache or Last-Modified header to everypage.

This behaiviour is really troubling when working with querystrings to get dynamic information, as IE considers it to be the same page (i.e.: http://example.com/?id=10) and serves the cached version.

I've solved it adding either a random number or a timestring to the querystring (as others have done) like this http://example.com/?id=10&t=2009-08-06_13:12:56 that I just ignore serverside.

Is there a better option? Is there another, cleaner way to acomplish this? I'm aware that POST isn't cached, but it is semanticaly correct to use GET here.

Reference: Random Querystring to avoid IE caching

stylesheet linked with question mark and numeric value

1 Answers1