function openWin(url, win, width, height) {
height = height + 120; // add on extra to allow for title and close window text
var leftPos = (screen.availWidth - width) / 2;
var topPos = (screen.availHeight - height) / 2;
var w = window.open(url, win, 'height=' + height + ', width=' + width + ', status=false, menubar=false,' + 'left=' + leftPos + ', top=' + topPos);
w.focus();
}