function apri_pop_up(theURL,winName,width,height) { //v2.0
if (document.all) { 
var x = window.top.screenLeft; 
var y = window.top.screenTop; 
var w = window.top.document.body.offsetWidth; 
var h = window.top.document.body.offsetHeight; 
} 
else { 
var x = window.screenX; 
var y = window.screenY; 
var w = window.outerWidth; 
var h = window.outerHeight; 
} 
var cntx = x + Math.round((w - width) / 2); 
var cnty = y + Math.round((h - height) / 2); 

features="top="+ cnty +",left="+ cntx+",width="+ width +", height="+height+",scrollbars=yes,toolbar=no";
window.open(theURL,winName,features);
}