function showFullScreen(url) {
   if (window.screen) {		
       w = screen.availWidth; h = screen.availHeight;
   } else {
       w = 640; h = 480;
   }
   bigshow = window.open( url, 'ext', 'toolbar, directories, location, menubar, scrollbars, status, resizable, top=0, left=0, screenX=0, screenY=0, width=' + w + ',height=' + h);
   if (window.focus) {bigshow.focus()}
}