lenville

// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating

// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel

// MIT license

(function() {
    var lastTime = 0;
    var vendors = ['ms', 'moz', 'webkit', 'o'];

lenville

function sendXMLHTTPRequest (successCallback, errorCallback) {
  var request = new XMLHttpRequest(),
      url = "",
      type;
  request.open("GET", url);
  request.onreadystatechange = function () {
    if (request.readyState === 4 && request.status === 200) {
      successCallback(request.responseText); // 不判断格式直接回调
    } else {
      errorCallback("error"); // 出错回调