CSS3 support for Internet Explorer 6, 7, and 8

What is it?

IE-CSS3 is a script to provide Internet Explorer support for some new styles available in the upcoming CSS3 standard.

How it works

If you’re viewing this page in Internet Explorer, some of the
elements have been rebuilt by the script in Vector Markup Language
(VML), an IE-specific vector drawing language. VML supports things that
are missing from IE’s CSS implementation like rounded corners and blur
effects.

How to use it

Just add CSS styles as you normally would, but include one new line:

.box {
  -moz-border-radius: 15px; /* Firefox */
  -webkit-border-radius: 15px; /* Safari and Chrome */
  border-radius: 15px; /* Opera 10.5+, future browsers, and now also Internet Explorer 6+ using IE-CSS3 */

  -moz-box-shadow: 10px 10px 20px #000; /* Firefox */
  -webkit-box-shadow: 10px 10px 20px #000; /* Safari and Chrome */
  box-shadow: 10px 10px 20px #000; /* Opera 10.5+, future browsers and IE6+ using IE-CSS3 */

  behavior: url(ie-css3.htc); /* This lets IE know to call the script on all elements which get the ’box’ class */
}

Issues and Workarounds

You would expect URLs in behavior: url(...) to be relative to the current directory as they are in a background-image: url(...) style for example, but instead Microsoft decided to ignore standards here and make them relative to the docroot instead. So behavior: url(ie-css3.htc) should work if ie-css3.htc is in the root directory of the site.

You will probably run into issues with z-index,
especially if embedding one IE-CSS3 enabled element inside of another.
There are two simple workarounds:

Set the z-index of the IE-CSS3 element to a number larger than its surrounding elements.
Make sure the IE-CSS3 element is positioned, such as with position: relative or position: absolute

Sometimes an IE-CSS3 element will show up at a
slightly different position than the original, untouched element. There
could be a few reasons for this:

You have broken tags somewhere in your markup, probably above the IE-CSS3 element.
You are experiencing misc IE6 and IE7 bugs. Try adding the styles zoom: 1 and/or position: relative to the IE-CSS3 element and its immediate parent. You could also try
removing any margins on the IE-CSS3 element and/or its parent, use
padding instead.

Styles and their status

Style	What works	What doesn’t work
border-radius	Setting a radius for all four corners Element borders	Setting a radius for individual corners separately
box-shadow	Blur size Offset	Any color other than #000
text-shadow	Blur size Offset Color	The shadow looks a little bit different than it does in FF/Safari/Chrome

This is a fork of Remiz Rahnas’s original script. Thanks Remiz!