here is the gradient css i have, but it doesn't work in IE9.. I'm confused

Code:
background: -moz-linear-gradient(top, #ffffff 0%, #dddd00 100%);
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#ffffff), color-stop(100%,#dddd00));
background: -webkit-linear-gradient(top, #ffffff 0%,#dddd00 100%);
background: -o-linear-gradient(top, #ffffff 0%,#dddd00 100%);
background: -ms-linear-gradient(top, #ffffff 0%,#dddd00 100%);
background: linear-gradient(to bottom, #ffffff 0%,#dddd00 100%);
filter: progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr='#ffffff', endColorstr='#dddd00');
i have tried putting quotes around the "progid.DXImage..." part but it didn't make any difference