Code-Chrome extension

//contentscript.js

function timedFunction() {
var txt ="shan";
chrome.extension.sendRequest({method:"text",key:txt}, function(response) {
                        d=response.data;
                        alert(d);
});
setTimeout("timedFunction()",2000);
}
timedFunction();

//background.html
<!DOCTYPE html>
<html>
  <head>
  </head>
  <body>
    <script type='text/javascript'>
chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
    if (request.method == "text")
    {
      sendResponse({data:request.key});
     }
    else
    {

     }
});

  </script>
  </body>
</html>