javascript判断有没装flash

<SCRIPT LANGUAGE="Javascript">
<!--
var flashinstalled = 0;
var flashversion = 0;
MSDetect = "false";
if (navigator.plugins && navigator.plugins.length)
{
  x = navigator.plugins["Shockwave Flash"];
  if (x)
  {
    flashinstalled = 2;
    if (x.description)
    {
      y = x.description;
      flashversion = y.charAt(y.indexOf('.')-1);
    }
  }
  else
    flashinstalled = 1;
  if (navigator.plugins["Shockwave Flash 2.0"])
  {
    flashinstalled = 2;
    flashversion = 2;
  }
}
else if (navigator.mimeTypes && navigator.mimeTypes.length)
{
  x = navigator.mimeTypes['application/x-shockwave-flash'];
  if (x && x.enabledPlugin)
    flashinstalled = 2;
  else
    flashinstalled = 1;
}
else
  MSDetect = "true";
// -->
</SCRIPT>