Force IE8 to IE7 Compatibility Mode

Is there a way that I can force IE8 users to enter IE7 compatibility mode when they hit my website so that I don’t have to change my working IE7 site?

Yes. There is. Details are on this Microsoft blog.

Essentially, there are two ways to implement this:

  • On a per-site basis, add a custom HTTP header

X-UA-Compatible: IE=EmulateIE7

  • On a per-page basis, add a special HTML tag to each document, right after the <head> tag

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />

I hope that works for you.  I understand from some that even with this setting, you might have to tweak a few things.