如何让label的text在10秒后清空？

JScript code

<script>
function Clear() 
{
        setTimeout(function(){document.getElementById('Label1').innerText='';}, 10000); 
    return 0;
}
</script>

C# code

private void Page_Load(object sender, System.EventArgs e)
{
    this.RegisterStartupScript("clear","<script>Clear();</script>");
}