function apri_pop_up(theURL,winName,width,height) { //v2.0

if (document.all) { 
var x = window.screenLeft; 
var y = window.screenTop; 
var w = window.document.body.offsetWidth; 
var h = window.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); 

//alert("w="+w+" h="+h+" "+cnty+" "+cntx);
if(winName=='tab'){
features="scrollbars=yes";
finestra=window.open(theURL,winName,features);
finestra.resizeTo(width+20,height+20);
finestra.moveTo(cntx,cnty);
finestra.focus();

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

}