<html>
<head>
<title></title>
<script language="JavaScript">
function Verify()
{
    if(event.propertyName == "value")
    {
        if(!/^\d*(\.\d{0,2})?$/.test(event.srcElement.value))
        {
            event.srcElement.value = event.srcElement.value.replace(/^([^\d]*)(\d*(\.\d{0,2})?)(.*)/g, "$2");
        }
    }
}
</script>
</head>
<body>
<input onpropertychange="Verify()">
</body>
</html>