<script type="text/javascript">
    
        function hasPlugin(name){
            name = name.toLowerCase();
            for (var i=0; i < navigator.mimeTypes.length; i++){
                if (navigator.mimeTypes[i].name.toLowerCase().indexOf(name) > -1){
                    return true;
                }
            }
        
            return false;
        }
        
        alert(hasPlugin("Flash"));   //参数仅需插件名
        
        alert(hasPlugin("QuickTime"));
        
        alert(hasPlugin("Java"));
    </script>