function centerPop(page, w, h) {
        var sw = screen.availWidth;
        var sh = screen.availHeight;
        var dx = sw / 2 - w / 2;
        var dy = sh / 2 - h / 2;
        var hwnd = window.open(page, "POPUP", "width="+w+",height="+h+",left="+dx+",top="+dy);
}