(function(window, document) {
'use strict';
varjsonp =function(url, data, callback) {
//1、挂载回调函数
varfnsuffix = Math.random().toString().replace('.','');
varcbFuncName ='my_json_cb'+ fnsuffix;
window[cbFuncName] = callback;
//2、将data转换成url字符串的形式
//{id=1,count=4}==>id=1&count=4
varquerystring = url.indexOf('?') == -1 ?'?':'&'; //判断url中最后是否有?,没有则为?
for(varkeyindata) {
querystring += key +'='+ data[key] +'&';
}
//3、处理url中回调函数 url+=callback=sdgade
querystring +='callback='+ cbFuncName;
//querystring=?id=1&count=4&callback=sdgade
//4、创建一个script标签
varscriptElement = document.createElement('script');
scriptElement.src = url + querystring;
//5、把script标签放到页面上
document.body.appendChild(scriptElement);
};
window.$jsonp = jsonp;
})(window, document)