检测用户是否安装RealPlayer播放器

<SCRIPT LANGUAGE=JavaScript>
  var RealMode=0;
  var RealPlayer5=0;
  var RealPlayer4=0;
  var RealPlayerG2=0;
 
if(navigator.userAgent.indexOf("MSIE")<0)
{
 numPlugins=navigator.plugins.length;
 for  (i=0;i<numPlugins;i++)
 {
  plugin=navigator.plugins[i];
  if(plugin.name.substring(0,10)=="RealPlayer")
   RealMode=1;
   }
}
</SCRIPT>
<SCRIPT LANGUAGE=VBScript> 
on error resume next 
RealPlayerG2=(NOTIsNull(CreateObject("rmocx.RealPlayerG2Control")))
RealPlayer5=(NOTIsNull(CreateObject("RealPlayer.RealPlayer(tm)ActiveXControl(32-bit)")))
RealPlayer4=(NOTIsNull(CreateObject("RealVideo.RealVideo(tm)ActiveXControl(32-bit)")))
</SCRIPT>

<SCRIPT LANGUAGE=JavaScript>
if(RealMode||RealPlayerG2||RealPlayer5||RealPlayer4)  {
  alert("RealPlayerplug-inisinstalled.");
}else{
  alert("RealPlayerplug-inisnotinstalled.");
}
</SCRIPT>