如何從一個Ajax請求之前訪問變量狀態回調函數

Question

EG

for(i in an_object){ 

     $.getJSON("http//www...." + "?callback=?",'', function(data){ 
       // do something using what the value of i from when the JSONP request was sent 
       // but i is always the last value in an_object because the loop 
       // has finished by the time the callback runs. 
      ); 
     }); 
} 

Answer 1

我通過將ajax調用放入匿名函數中解決了這個問題。例如：

for(i in an_object){ 

    (function(i){ 

     $.getJSON("http//www...." + "?callback=?",'', function(data){ 
       // i now remembers its state. 
     }); 
    })(i); 
} 

Answer 2

如果你只需要一個變量，你可以使用代理綁定它作爲背景的功能：

var state=1, callbackfunction = function(data) { 
    if (this===1) { 
    //something based on state 
    } 
} 

$.getJSON("http//www..",'', jQuery.proxy(callbackfunction , state));