****** index.html
 
<html>
    <head>
        <title></title>
    </head>
    <body>
        <script>
            var dude = new Worker('my_worker.js');
            dude.onmessage = function(e) {
                alert(e.data);
            };
            dude.postMessage('go for it');
        </script>
    </body>
</html>
 
 
 
****** my_worker.js
 
makeRequest = function() {
    var req = new XMLHttpRequest();
    
    req.open('GET', 'http://www.google.com/');
 
    req.onreadystatechange = function (e) {
      if (req.readyState == 4) {
         if(req.status == 200)
          postMessage(req.responseText);
         else
          postMessage("we have gremlins");
      }
    };
 
    req.send(null);
}
 
onmessage = function(e) {
    makeRequest();
};
 