<div id="supported"></div>  
<div id="unsupported"></div>  
<button onclick="worker();">click me</button>  
<script type="text/javascript">  
   function worker()   
   {  
    if(typeof(Worker)!=="undefined"){  
     document.getElementById("supported").innerHTML="Supporting the browser";  
      }  
     else  
      {  
      document.getElementById("unsupported").innerHTML="Not supporting";}  
   }  
</script>