function openwin(theURL,pwidth,pheight) { 
 var leftwidth = (window.screen.width-pwidth)/2;
 var topwidth = (window.screen.height-pheight)/2;
 window.open(theURL,'','menubar=no,toolbar=no,scrollbars=yes,location=no,left='+leftwidth+',top='+topwidth+',width='+pwidth+',height='+pheight);
}