var myWindow = null;
function centerPopup(myURL, myTitle, myW, myH, myScroll) {
	myLeftPosition = (screen.width) ? (screen.width - myW)/2 : 0;
	myTopPosition = (screen.height) ? (screen.height - myH)/2 : 0;
	mySettings = 'height=' +myH+ ', width=' +myW+ ', top=' +myTopPosition+ ', left=' +myLeftPosition+ ',scrollbars=' +myScroll+ ', resizable=1';
	myWindow = window.open(myURL, myTitle, mySettings)
}