JavaScript clicks the entire page to turn gray effect (can do exit effect). _javascript Tips

Click the effect of the whole page to turn gray (you can do the exit effect).
Note: The page header must be added
<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">
Otherwise the effect cannot be achieved

<a href= "#" onclick= ' return Log_out () ' > Safe exit </a>
<script language= "JavaScript" >
<!--
function Log_out ()
{
HT = document.getElementsByTagName ("html");
Ht[0].style.filter = "Progid:DXImageTransform.Microsoft.BasicImage (grayscale=1)";
if (confirm) (' Are you sure you want to quit management? '))
{
Window.location.href= "logout.asp";
}
Else
{
Ht[0].style.filter = "";
return false;
}
}
-->
</script>