title: javascript Ajax method in different browser has different result
body: <p>I have a code like this :</p>
  
  <pre><code>var width = [];
  
  $.ajax({
     url : "http://xxx.xxx.xxx" ,
     type : "Get",
     dataType: "json",
     async   : true,
     success : function(data){
         for (var index in data)
         {
             var options = data[index].option;
             var position = (++index);
             width[index] = new Array();
             for (var keys in options)
             {
                width[index][keys] = options[keys].votes;
             }
         }
     }
  });
  </code></pre>
  
  <p>in the chrome browser, it works fine, but in the safari, the error look likes:</p>
  
  <pre><code>TypeError: undefined is not an object (evaluating 'width[index][keys] = options[keys].votes')
  </code></pre>
  
  <p>But if I open debug mode in safari, there is no error, so what's the problem in this code?</p>