function open_popup(externalURL,replacewindow)
	{
	var replace;

	if (replacewindow=='undefined')
	   replace='win';
	else
	   replace=replacewindow;

	scrWidth = window.screen.availWidth - 50 ;
	scrHeight = window.screen.availHeight - 200 ;
	scrLeft = 0;
	scrTop=0;
	var strFeatures = "scrollbars=yes,status=no,toolbar=no,menubar=no,location=no,resizable=yes,left=" + scrLeft + ",top=" + scrTop + ",height=" +  scrHeight + ",width=" + scrWidth

	var myWin = window.open(externalURL, replace, strFeatures, 0);
	myWin.focus(); 
	return;
	}