This code is placed between the <head> and </head> tags within the window that is opened (the popup window). 

<SCRIPT LANGUAGE="JAVASCRIPT" TYPE="TEXT/JAVASCRIPT">

var StayAlive = 15; // Number of seconds to keep window open
function KillMe(){
setTimeout("self.close()",StayAlive * 1000);
}

</SCRIPT>

Add the following code to the <BODY> tag of the popup window. ( ex. <body onload="KillMe();self.focus()"> )
Note: self.focus() ensures the popup window appears on top of all other windows.

onload="KillMe();self.focus()"