1<!DOCTYPE html> 2<!-- 3 * Copyright (c) 2010 The Chromium Authors. All rights reserved. Use of this 4 * source code is governed by a BSD-style license that can be found in the 5 * LICENSE file. 6--> 7<html> 8 <head> 9 </head> 10 <body> 11 <script> 12 /** 13 * Performs an XMLHttpRequest to Twitter's API to get trending topics. 14 * @param callback Function If the response from fetching url has a 15 * HTTP status of 200, this function is called with a JSON decoded 16 * response. Otherwise, this function is called with null. 17 */ 18 function fetchTwitterFeed(callback) { 19 var xhr = new XMLHttpRequest(); 20 xhr.onreadystatechange = function(data) { 21 if (xhr.readyState == 4) { 22 if (xhr.status == 200) { 23 var data = JSON.parse(xhr.responseText); 24 callback(data); 25 } else { 26 callback(null); 27 } 28 } 29 } 30 // Note that any URL fetched here must be matched by a permission in 31 // the manifest.json file! 32 var url = 'http://search.twitter.com/trends/current.json?exclude=hashtags'; 33 xhr.open('GET', url, true); 34 xhr.send(); 35 }; 36 37 /** 38 * Handles data sent via chrome.extension.sendRequest(). 39 * @param request Object Data sent in the request. 40 * @param sender Object Origin of the request. 41 * @param callback Function The method to call when the request completes. 42 */ 43 function onRequest(request, sender, callback) { 44 // Only supports the 'fetchTwitterFeed' method, although this could be 45 // generalized into a more robust RPC system. 46 if (request.action == 'fetchTwitterFeed') { 47 fetchTwitterFeed(callback); 48 } 49 }; 50 51 // Wire up the listener. 52 chrome.extension.onRequest.addListener(onRequest); 53 </script> 54 </body> 55</html>