var w = 480, h = 340;

if (document.all || document.layers) {
   w = screen.availWidth;
   h = screen.availHeight;
}else{
	w = screen.width;
	h = screen.height;
}

var url;

var popW;

var popH;

function popUp(url, popW, popH){ 
var leftPos = (w-popW)/2, topPos = (h-popH)/2;
window.open(url,'popup','width=' + popW + ',height=' + popH + ',top=' + topPos + ',left=' + leftPos);
}





//--></script>