在Javascript循环中显示JSON数据

Question

I am having an issue displaying json data. I have searched and found many examples, but for some reason I get the "Cannot read property 'length' of undefined" error, because "var object = notes.data;" comes back as undefined.

Why is object undefined? From everything I can see I am doing it right.

My json that is returned.

{  
   "data":[  
      {  
         "NumberOfAnswers":25,
         "Answer":"51-89 Percent of all items in section are <b>IN STOCK<\/b>",
         "Percent":54.35
      },
      {  
         "NumberOfAnswers":21,
         "Answer":"90-100 Percent of all items in section are <b>IN STOCK<\/b>",
         "Percent":45.65
      }
   ]
}

And here is the function to display it. (With some debugging code as well)

 function format(notes) {
     console.log(notes); //this displays the json
     var object = notes.data;
     console.log(object);
     var i;
     for (var i = 0; i < object.length; i++) {
         var Result = object[i];
         var Answer = Result.Answer;
         console.log(Answer)
     }

  }

Here is the ajax function:

 $.ajax({
     type: 'post',
     url: '/rmsicorp/clientsite/pacingModal/surveyajax2.php',
     success: function(result) {
         if (row.child.isShown()) {
             row.child.hide();
             tr.removeClass('shown');
             detailsrows.splice(RowID, 1);
         } else {
             row.child(format(result)).show();
             tr.addClass('shown');
             if (RowID === -1) {
                 detailsrows.push(tr.attr('id'));
             }

         }
     }
 });

Answer 1

Most likely, the response is still in string format. You can add JSON.parse to convert it to an object and then be able too access the data property.

Try modifying your function like this to see if it fixes the problem.

function format(notes) {
   console.log(notes); //this displays the json
   // The following converts the response to a javascript object
   // and catches the exception if the response is not valid JSON
   try {
      notes = JSON.parse(notes);
   } catch(e) {
      console.log('notes is not valid JSON: ' + e);
   }
   var object = notes.data;
   console.log(object);
   var i;
   for (var i = 0; i < object.length; i++) {
      var Result = object[i];
      var Answer = Result.Answer;
      console.log(Answer)
   }
}