text: /**
   * =============================================================================
   * ************   浏览器兼容性问题修复   ************
   * =============================================================================
   */
  
  /**
   * requestAnimationFrame
   * cancelAnimationFrame
   */
  (function () {
    var lastTime = 0;
  
    if (!window.requestAnimationFrame) {
      window.requestAnimationFrame = window.webkitRequestAnimationFrame;
      window.cancelAnimationFrame = window.webkitCancelAnimationFrame;
    }
  
    if (!window.requestAnimationFrame) {
      window.requestAnimationFrame = function (callback, element) {
        var currTime = new Date().getTime();
        var timeToCall = Math.max(0, 16.7 - (currTime - lastTime));
  
        var id = window.setTimeout(function () {
            callback(currTime + timeToCall);
          }, timeToCall);
  
        lastTime = currTime + timeToCall;
        return id;
      };
    }
  
    if (!window.cancelAnimationFrame) {
      window.cancelAnimationFrame = function (id) {
        clearTimeout(id);
      };
    }
  })();
  