动态执行javascript脚本完成后清理

var do_jsonp_id = 1;

function doJsonp(url, callback, timeout) {
  var name = "do_jsonp_callback_"+(do_jsonp_id++);
  var ele = document.createElement('script');
  var timer;

  window[name] = function() {
    //清理计时器
    window.clearTimeout(timer);
    //回调回调函数
    callback.apply(this, arguments);
    //清理元素
    ele.parentNode.removeChild(ele);
    //清理回调
    delete window[name];
  };

  url += ((url.indexOf("?") == -1) ? '?' : '&') + "callback=" + name;

  ele.src = url;

  //超时处理
  timer = window.setTimeout(function(){
    //清理元素
    ele.parentNode.removeChild(ele);
    //清理回调
    delete window[name];
  }, timeout||30000);

  //执行请求
  document.getElementsByTagName('head')[0].appendChild(ele);
}