If you put an HTML comment above the doctype declaration, it causes IE7 to enter quirks mode, but not any other browsers.
<!-- This forces quirks mode in IE7 only -->
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=Edge">
<title>Quirks mode in IE7!</title>
</head>
<body></body>
</html>
Wow! That’s neat, I guess?
Why would anyone want to do this? Well, I had an application that required the IE6 box model for some pieces (so we could have 100% width input elements (with padding) inside dynamically sized table columns (with padding)). Forcing IE7 into quirks mode causes it to follow the IE6 box model, but I wanted to keep IE8+ in standards mode since you can use the box-sizing CSS property to achieve the correct box model in more modern browsers.
So, you see, there’s at least one use case.
Not this fix wil put IE9 in IE5 quirks mode which is probably not what you want.
Thanks Willem, I had forgotten to include the `< meta http-equiv="X-UA-Compatible" content="IE=Edge" >` tag which should make it work as expected in IE9 as well. I added it into the post.