Gradients in Internet Explorer 9

Looks like I'm a little late to the party, but here's an example for some of the top browsers:

/* IE10 */ 
background-image: -ms-linear-gradient(top, #444444 0%, #999999 100%);

/* Mozilla Firefox */ 
background-image: -moz-linear-gradient(top, #444444 0%, #999999 100%);

/* Opera */ 
background-image: -o-linear-gradient(top, #444444 0%, #999999 100%);

/* Webkit (Safari/Chrome 10) */ 
background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #444444), color-stop(1, #999999));

/* Webkit (Chrome 11+) */ 
background-image: -webkit-linear-gradient(top, #444444 0%, #999999 100%);

/* Proposed W3C Markup */ 
background-image: linear-gradient(top, #444444 0%, #999999 100%);

Source: http://ie.microsoft.com/testdrive/Graphics/CSSGradientBackgroundMaker/Default.html

Note: all of these browsers also support rgb/rgba in place of hexadecimal notation.

The best cross-browser solution is

background: #fff;
background: -moz-linear-gradient(#fff, #000);
background: -webkit-linear-gradient(#fff, #000);
background: -o-linear-gradient(#fff, #000);
background: -ms-linear-gradient(#fff, #000);/*For IE10*/
background: linear-gradient(#fff, #000);
filter: progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr='#ffffff', endColorstr='#000000');/*For IE7-8-9*/ 
height: 1%;/*For IE7*/ 

You still need to use their proprietary filters as of IE9 beta 1.

IE9 currently lacks CSS3 gradient support. However, here is a nice workaround solution using PHP to return an SVG (vertical linear) gradient instead, which allows us to keep our design in our stylesheets.

<?php

$from_stop = isset($_GET['from']) ? $_GET['from'] : '000000';
$to_stop = isset($_GET['to']) ? $_GET['to'] : '000000';

header('Content-type: image/svg+xml; charset=utf-8');

echo '<?xml version="1.0"?>
';

?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="100%" height="100%">
    <defs>
        <linearGradient id="linear-gradient" x1="0%" y1="0%" x2="0%" y2="100%">
            <stop offset="0%" stop-color="#<?php echo $from_stop; ?>" stop-opacity="1"/>
            <stop offset="100%" stop-color="#<?php echo $to_stop; ?>" stop-opacity="1"/>
        </linearGradient>
    </defs>
    <rect width="100%" height="100%" fill="url(#linear-gradient)"/>
</svg>

Simply upload it to your server and call the URL like so:

gradient.php?from=f00&to=00f

This can be used in conjunction with your CSS3 gradients like this:

.my-color {
    background-color: #f00;
    background-image: url(gradient.php?from=f00&to=00f);
    background-image: -webkit-gradient(linear, left top, left bottom, from(#f00), to(#00f));
    background-image: -webkit-linear-gradient(top, #f00, #00f);
    background-image: -moz-linear-gradient(top, #f00, #00f);
    background-image: linear-gradient(top, #f00, #00f);
}

If you need to target below IE9, you can still use the old proprietary 'filter' method:

.ie7 .my-color, .ie8 .my-color {
    filter: progid:DXImageTransform.Microsoft.Gradient(startColorStr="#ff0000", endColorStr="#0000ff");
}

Of course you can amend the PHP code to add more stops on the gradient, or make it more sophisticated (radial gradients, transparency etc.) but this is great for those simple (vertical) linear gradients.

The code I use for all browser gradients:

background: #0A284B;
background: -webkit-gradient(linear, left top, left bottom, from(#0A284B), to(#135887));
background: -webkit-linear-gradient(#0A284B, #135887);
background: -moz-linear-gradient(top, #0A284B, #135887);
background: -ms-linear-gradient(#0A284B, #135887);
background: -o-linear-gradient(#0A284B, #135887);
background: linear-gradient(#0A284B, #135887);
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#0A284B', endColorstr='#135887');
zoom: 1;

You will need to specify a height or zoom: 1 to apply hasLayout to the element for this to work in IE.

Update:

Here is a LESS Mixin (CSS) version for all you LESS users out there:

.gradient(@start, @end) {
    background: mix(@start, @end, 50%);
    filter: ~"progid:DXImageTransform.Microsoft.gradient(startColorStr="@start~", EndColorStr="@end~")";
    background: -webkit-gradient(linear, left top, left bottom, from(@start), to(@end));
    background: -webkit-linear-gradient(@start, @end);
    background: -moz-linear-gradient(top, @start, @end);
    background: -ms-linear-gradient(@start, @end);
    background: -o-linear-gradient(@start, @end);
    background: linear-gradient(@start, @end);
    zoom: 1;
}