function popup(pageToLoad, winName, width, height) {
    var frameName = window.name; 
    if(frameName!='') { 
      if(pageToLoad.indexOf('?')!=-1) { pageToLoad+='&pFrame=' + window.name;} 
      else { pageToLoad+='?pFrame=' + window.name;} 
    }
    xposition=100; yposition=100;
    if ((parseInt(navigator.appVersion) >= 4 )){
        xposition = (screen.width - width) / 2;
        yposition = (screen.height - height) / 2;
    }
    args = "width=" + width + "," + "height=" + height + "," + "location=" + location + "," + "menubar=0,resizable=0,scrollbars=1,status=0,titlebar=0,toolbar=0,screenx=" + xposition + "," + "screeny=" + yposition + "," + "left=" + xposition + "," + "top=" + yposition;
    window.open(pageToLoad, winName, args);
}