parsing JSON using javascript gives me undefined while getting the value from the json response

Question

i am parsing an json string usin javascript

    {
      "head":   {
        "example": "0"
         },
      "res":   {
        "@test": "121",
        "@found": "5"
     }
}

i am getting the http response from the remote site and i am using javascript to extract the @found value .i used the below code .

 var json=eval('('+request.responseText+')');
        alert(json.head.res.@found);

gives me a null value can u please tell me how can i parse this.

res is parallel to head. Iterate till what depth it returns object. Try alert(json.res.@found); — hungryMind, Oct 11 '11 at 13:18

score 3 · Answer 1 · edited May 23 '17 at 10:34

alert(json.head.res['@found']);

@ is not valid to start a variable name, so you have to use bracket notation. Or change the variable name to be valid.

Basically, in regular expression form: [a-zA-Z_$][0-9a-zA-Z_$]*. In other words, the first character can be a letter or _ or $, and the other characters can be letters or _ or $ or numbers.

What characters are valid for JavaScript variable names?

Per Topera's answer head and res are on the same level in your object not nested.

score 1 · Answer 2 · answered Oct 11 '11 at 13:18

1

Attribute "res" is not inside "head" attribute.

Try this: json.res['@found']

answered Oct 11 '11 at 13:18

Topera

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score 0 · Answer 3 · edited Aug 01 '12 at 14:14

0

alert(json.res['@found']);

res is not inside head.

edited Aug 01 '12 at 14:14

bluish

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answered Oct 11 '11 at 13:18

Maurice Perry

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score 0 · Answer 4 · answered Oct 11 '11 at 13:19

0

Try json.res['@found']. JavaScript object properties that are not valid variable names cannot be accessed using dot notation. Also, as noted by others, @found is not in head.

answered Oct 11 '11 at 13:19

abesto

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gion_13 · Answer 5 · 2011-10-11T13:24:59.593

0

fix these 3 things :

@ is not a valid variable name character. you should consider the [] syntax instead of the "dot" one.
res is not in head.
please don't use eval. I strongly advise you to use JSON.parse instead of eval

var json = JSON.parse(request.responseText);
alert(json.res['@found']);

edited Oct 11 '11 at 13:24

answered Oct 11 '11 at 13:19

gion_13

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thanks for your advice and the json is converted from xml so it has the name starts with @ .i used json-lib to convert it in java . – Ramesh Oct 11 '11 at 13:35

parsing JSON using javascript gives me undefined while getting the value from the json response

5 Answers5