You will have to use the easydate jQuery plugin
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>Untitled Page</title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script type = "text/javascript" src = "http://easydate.parshap.com/files/jquery.easydate-0.2.4.js"></script>
<script type="text/javascript">
$(function () {
$(".relative-date").easydate();
});
</script>
</head>
<body>
<form id="form1" runat="server">
<span class="relative-date">Mon, 16 Jul 2012 22:18:04 -0700</span><br />
<span class="relative-date">Tue, 17 Jul 2012 01:48:04 -0700</span><br />
<span class="relative-date">Sun, 15 Jul 2012 16:18:04 -0700</span><br />
<span class="relative-date">Sat, 12 May 2012 22:18:04 -0700</span><br />
</form>
</body>
</html>
Demo
