I tried using the "ultimate CSS gradient generator" and it produced the following:
background: #657575; /* Old browsers */
background: -moz-linear-gradient(left, #657575 0%, #758585 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, right top, color-stop(0%,#657575), color-stop(100%,#758585)); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(left, #657575 0%,#758585 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(left, #657575 0%,#758585 100%); /* Opera11.10+ */
background: -ms-linear-gradient(left, #657575 0%,#758585 100%); /* IE10+ */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#657575', endColorstr='#758585',GradientType=1 ); /* IE6-9 */
background: linear-gradient(left, #657575 0%,#758585 100%); /* W3C */
But is seems that the gradient does not work at least with my version of IE9. So is there any way I can produce a simple horizontal gradient with IE9?