var popupWin = null;
function openPopup(url, width, height) {

    // golden rectangle 1:1.618
    width = init(width, 500);
    height = init(height, Math.round(width * 1.618));

    //if (popupWin != null && popupWin.open) {
        //popupWin.focus();
    //}
    
    // toolbar,location,menubar,directories,resizable,scrollbars,status
    popupWin = window.open(url, 'PopupWindow', 'width=' + width + ',height=' + height + ',resizable');
    popupWin.focus();
}

function closePopup() 
{
    if (popupWin != null && popupWin.open) {
        popupWin.close();        
    }
}