Short answer:
Put this in your head tag to tell the browser that your page works in IE 8:
<meta http-equiv="X-UA-Compatible" content="IE=8" />
Also as per Jon Hadleys comment, to ensure the latest (not just IE8) rendering engine is used, you could use the following:
<meta http-equiv="X-UA-Compatible" content="IE=edge">
To quote the IEBlog:
“Browser Mode” affects the user agent
string, version vector used when
evaluating conditional comments, and
the rendering mode.
It's detailed a bit more on http://msdn.microsoft.com/en-us/library/dd565624(VS.85).aspx.
As you can clearly see, you wouldn't be able to affect all of these things anyway: by the time you tell the browser to act like IE7, it's already acting as IE8.
Perhaps the real question is: Why does it matter that much to you what the browser mode is? The document mode is what you should be most concerned with - everything the browser mode changes as far as the rendering is concerned relate to stuff that is excluded/included but version checking, and users aren't going to look in the developer tools anyway, so they won't care.
Instead of wasting a lot of time getting it to look like pure compatibility mode in the developer tools, you should rather go and make sure that user agent string checking and conditional comments make it so that IE7 and IE8 get the same material to work with, and then leave the EmulateIE7 in.
EDIT:
The problem is your version checks, and as I promised below, I'm going to tell you where the problem is.
If you use the developer tools to debug the menu placement script, you can dig down and see that the execution path for get_x_position differs when the browser reports itself as IE7 or IE8: is_ie5up
is set to true for IE7 mode, and false for IE8 mode. This results in very different values being returned.
At this point, we must go back to where this variable is set:
var is_ie5up = (is_ie6up || (is_ie && !is_ie3 && !is_ie4));
As you can see, this depends on the value of is_ie6up
, so let's have a look at the surrounding code...
var is_ie8up = (is_ie8 || is_ie9up);
var is_ie7up = (is_ie7 || is_ie8up);
var is_ie7up = (is_ie7);
var is_ie6up = (is_ie6 || is_ie7);
var is_ie5up = (is_ie6up || (is_ie && !is_ie3 && !is_ie4));
var is_ie5_5up = (is_ie6up || (is_ie && !is_ie3 && !is_ie4 && !is_ie5));
...do you spot the flaw (Hint: compare lines 2 and 4 of that snippet)?
That's right: is_ie6up
is not set to true unless the browser is exactly IE6 or IE7. The proper line should of course read
var is_ie6up = (is_ie6 || is_ie7up);
...but wait. That's no good either, because line 3 of the snippet changes is_ie7up
to only be true if the browser is exactly IE7! So, you need to delete the overwriting of is_ie7up
, and fix the setting of is_ie6up
.
My guess is that you have the EXACT same problem on the other site: you've messed up the browser checks in much the same way.
Best Answer
According to Just The Facts: Recap of Compatibility View you've declared [your website] "ready" for Internet Explorer 8 through the use of the versioning tag. The Compatibility View button should not be displayed:
If you're using an HTTP header, have you used Fiddler to verify that the
X-UA-Compatible
header is actually being delivered on every page?If you're using a
META
tag, then according to META Tags and Locking in Future Compatibility:Lastly, is IE8 actually in Compatibility View when the button shows up? If so, it is possible that your website is in IE8's compatibility list from Microsoft, or in the local client configuration:
Tools
>Compatibility View Settings