function openPopup(url,title, popW,popH){
var   w = screen.availWidth;
var   h = screen.availHeight;
var leftPos = (w-popW)/2 ;
var topPos = (screen.availHeight-popH)/2;
window.open(url,title,'width=' + popW + ',height=' + popH + ',top=' + topPos + ',left=' + leftPos + ',status=yes,location=no,toolbar=no,menubar=no,scrollbars=yes,resizable=yes');
}