function popUp(url,wd,ht){
        var args= "height="+ht+",innerHeight="+ht+",width="+wd+",innerWidth="+wd;
    if (window.screen)
    {
        var avht = screen.availHeight;
        var avwd = screen.availWidth;
        var xcen = (avwd - wd) / 2;
        var ycen = (avht - ht) / 2;
        args += ",left=" + xcen + ",screenX=" + xcen;
        args += ",top=" + ycen + ",screenY=" + ycen + ",resizable=no, scrollbars=no";
    }

  popwin=window.open(url,"newwindow",args)
}