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javascriptjqueryajaxjquery-callback

Which jQuery callback fired?

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

Solution

  • 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);
    }
});