触发了哪个jQuery回调？ [重复]

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            <div class="grid--cell mb0 mt8">Closed <span title="2012-11-26 03:09:50Z" class="relativetime">7 years ago</span>.</div>
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Possible Duplicate:
Javascript closure inside loops - simple practical example

Let's imagine you create some ajax requests in a for-loop like this:

$(function(){
    for(var i=0;i<10;i++){
      $.ajax({
        url : '/',
        success : function(){
          console.log('callback '+i+' fired!');
        }
      });
    }
});

Of course, the callback will log 'callback 10 fired' every time because the callbacks are executed asynchronous. The question is: how can you know which callback fired?

jsfiddle

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Anonymous self-invoked function will solve this closure issue:

$(function(){
    for(var i=0;i<10;i++){
      (function(i) {
          $.ajax({
            url : '/',
            success : function(){
              console.log('callback '+i+' fired!');
            }
          });
      })(i);
    }
});

By passing the current value of i as part of a closure:

$(function(){
    for(var i=0;i<10;i++){
      $.ajax({
        url : '/',
        success : (function(i){
          return function(){console.log('callback '+i+' fired!');}
        })(i)
      });
    }
});

Here is a demo: http://jsfiddle.net/rRwgW/4/

Note: you don't actually need to wrap the entire ajax call in an IIFE, just the callback that needs to refer to the value of i.

create a scope with an immediately invoked function expression:

$(function(){
    for(var i=0;i<10;i++){
      (function(i){
        $.ajax({
          url : '/',
          success : function(){
            console.log('callback '+i+' fired!');
          }
        });
      })(i);
    }
});