Question

I’ve an application written in Java and a webapp associated written essentially with javascript. I was running on IE7 and had no issues. But lately, I upgraded to IE8, and since then I’ve encountered a lot of problems…
No matters which versions of jquery i used, it crashes. I don’t have any javascript error messages, but CSS and other methods are not been used…
I found here on StackOverflow a guy with a similar problem, he added this to his header : <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />
Indeed, it works for me, but i do not know what that changes on my page. Does this meta change the interpretation of the CSS only ? Javascript ?

Thanks for your answer

Answer 1

X-UA-Compatible is Microsoft’s answer to making IE switch rendering modes for a site. The main issue that companies have with upgraded their IE installs is compatibility with web applications built to run on older versions of IE. This meta flag is used to tell newer versions of IE how they should process the current document.

In your example, the X-UA-Compatible value is telling IE to emulate IE7 rendering. If a user visited your site using IE8, it will see this flag and switch to IE7 compatibility mode and mimic its capabilities. You can read more about this at Defining Document Compatibility on MSDN.

However, if your JS is breaking in a browser then you should fix it rather than relying on this sort of cheap hack (in my opinion). While useful for quickly patching the issue you can’t guarantee that it will always work, and you may encounter issues in other browsers that do not understand X-UA-Compatible which is proprietary to IE.

If you struggle to fix your problem at the source, perhaps you can post a new question here for the SO users to take a look.