jsonp牽扯到同源策略、跨域等問題，這裏不細說了.

實現就是創建動態的script標簽來請求後臺地址：

示例：

 jsonp(‘xxx.php‘, { uid: 1 }, function (res) {
      console.log(res)
    })

實例:

 jsonp(‘http://localhost/server.php‘, { uid: 1 }, function (res) {
      console.log(res)
    })

 1     function jsonp (url, params, callback) {
 
 2       var funcName = ‘jsonp‘ + Date.now() + Math.random().toString().substr(2, 5)
 3 
 4       if (typeof params === ‘object‘) {
 5         var tempArr = []
 6         for (var key in params) {
 7           var value = params[key]
 8           tempArr.push(key + ‘=‘ + value)
 9         }
 
10         params = tempArr.join(‘&‘)
11       }
12 
13       var script = document.createElement(‘script‘)
14       script.src = url + ‘?‘ + params + ‘&callback=‘ + funcName
15       document.body.appendChild(script)
16 
17       window[funcName] = function (data) {
18         callback(data)
 
19         delete window[funcName]
20         document.body.removeChild(script)
21       }
22     }

javascript - 封裝jsonp