function openNewWindow(URLtoOpen,windowName,width,height) {
    x = (640 - width)/2, y = (480 - height)/2;

    if (screen) {
        y = (screen.availHeight - height)/2;
        x = (screen.availWidth - width)/2;
    }

    window.open(URLtoOpen,windowName,'width='+width+',height='+height+',screenX='+x+',screenY='+y+',top='+y+',left='+x+',toolbar=no,scrollbars=no,resizable=no');
}

function openResizeWindow(URLtoOpen,windowName,width,height) {
    x = (640 - width)/2, y = (480 - height)/2;

    if (screen) {
        y = (screen.availHeight - height)/2;
        x = (screen.availWidth - width)/2;
    }

    window.open(URLtoOpen,windowName,'width='+width+',height='+height+',screenX='+x+',screenY='+y+',top='+y+',left='+x+',toolbar=no,scrollbars=yes,resizable=yes');
}