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up vote 0 down vote favorite

I am able to pass an entire JSON object but am unable to index any information from it.

For instance the following code will put the entire JSON string as a single item in an unordered list

    <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8" />
    <title>Victoria Traffic</title>
</head>
<body>
    <div id="placeholder"></div>
        <script src="http://code.jquery.com/jquery-1.7.1.min.js"></script>
    <script>
    $.getJSON('http://whateverorigin.org/get?url=' + encodeURIComponent('http://traffic.vicroads.vic.gov.au/maps.json') + '&callback=?', function(data){
        var output = "<ul>";
        output += data.contents;
        output += "</ul>";
        document.getElementById("placeholder").innerHTML = output;
  });
    </script>
</body>
</html>

However the following code will not output anything with the console saying: Cannot read property '0' of undefined.

    <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8" />
    <title>Victoria Traffic</title>
</head>
<body>
    <div id="placeholder"></div>
        <script src="http://code.jquery.com/jquery-1.7.1.min.js"></script>
    <script>
    $.getJSON('http://whateverorigin.org/get?url=' + encodeURIComponent('http://traffic.vicroads.vic.gov.au/maps.json') + '&callback=?', function(data){
        var output = "<ul>";
        output += data.contents.incidents[0].id;
        output += "</ul>";
        document.getElementById("placeholder").innerHTML = output;
  });
    </script>
</body>
</html>

What am I doing wrong?

share|improve this question
    
What is data.contents? It evidently doesn't contain a property named incidents. – p.s.w.g Feb 3 '14 at 22:56
1  
Without seeing the JSON data we really can't tell what is going wrong. – Ken Herbert Feb 3 '14 at 22:56
up vote 1 down vote accepted

The response from whateverorigin.org appears to be JSON contained within JSON:

{"contents": "{\"incidents\": ...}"}

While getJSON() will parse the initial response for you, you'll have to parse the inner value yourself:

var contents = $.parseJSON(data.contents);

var output = "<ul>";
output += contents.incidents[0].id;
output += "</ul>";
share|improve this answer

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