时间比较问题

下面的程序结果有问题，哪位js高手帮忙解释下，谢谢了。
<html>
<head>
<script type="text/javascript">
function startTime()
{
var myDate=new Date();
myDate.setFullYear(2012,8,8);var today = new Date();if (myDate>today)
{
alert("Today is before 8th August 2012");
}
else
{
alert("Today is after 8th August 2012");
}
}
</script>
</head><body onload="startTime()">
</body>
<html>