function open_window(mypage,myname,w,h,features) {
   if(screen.width){
   var winl = (screen.width-w)/2;
   var wint = (screen.height-h)/2;
   }else{winl = 0;wint =0;}
   if (winl < 0) winl = 0;
   if (wint < 0) wint = 0;
   var settings = 'height=' + h + ',';
   settings += 'width=' + w + ',';
   settings += 'top=' + wint + ',';
   settings += 'left=' + winl + ',';
   settings += features;
   win = window.open(mypage,myname,settings);
   win.window.focus();
}