Firefox – Stop Firefox from asking to install flash and other plugins

Since both Firefox and Safari use the system-wide installation of Flash, I don't think this is doable. However: Chrome uses it's own Flash-bundle. If you uninstall flash on your system, and then use Chrome to view Flash-sites, it would not be loaded at all in Safari, and work fine in Chrome.

See Gruber's post on this for more info.

<script type="text/javascript">
var disabled_message = "";
document.oncontextmenu = function() 
{ 
   return false; 
}
document.onmousedown = function md(e) 
{ 
  try 
  { 
     if (event.button==2||event.button==3) 
     {
        if (disabled_message != '')
           alert(disabled_message);
        return false; 
     }
  }  
  catch (e) 
  { 
     if (e.which == 3) return false; 
  } 
}
</script>

A script that i used on my websites. it is extracted from WYSIWYG ready to use JavaScript.