Weird results from JSON returned array

Question

PHP

$table = mysql_real_escape_string($_REQUEST['table']);

$query  = "SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.Columns where TABLE_NAME = '$table'";
$result = mysql_query($query);
$arr1 = array();
while($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
    $arr1[] = $row['COLUMN_NAME'];
}
echo json_encode($arr1);

}

Javascript/Jquery

$("#verticalSelect").change(function() {
    var table = $("#verticalSelect option:selected").attr('value');

    $.post(PROCESSORFILE, {"task": "getTableDupeFields", "table": table}, function(data) {
        $.each(data, function(key, value){
            $("#test-area").append(key+' is: '+value+'<br/>');
        });
        alert(data);
    });
});

Now with the alert of the returned JSON variable I get the result I expect.

["lead_id", "callcenter", "monkey" ...]

But with the Jquery.each() function I get this:

0:is: [
1:is: "
2:is: l
3:is: e
4:is: a
5:is: d
6:is: _
7:is: i
8:is: d
9:is: "
10:is: ,
11:is: "
12:is: c
13:is: a
14:is: l
15:is: l
16:is: c
17:is: e
18:is: n
19:is: t
20:is: e
21:is: r

Every character of the returned array is looped instead of every discreet value. What is the proper way of handling JSON returned arrays?

The proper way is to convert the string into native data types ;) — Felix Kling
– Felix Kling, Commented Sep 3, 2012 at 22:53

Musa · Accepted Answer · 2012-09-03 22:53:01Z

3

You either need to set your response header to application/json or specify the dataType in $.post to be 'json'

answered Sep 3, 2012 at 22:53

Musa

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4 Comments

Pointy Over a year ago

Does $.post() detect the Content-Type? That's nice if so :-) I know that $.ajax() doesn't but I guess it would kind-of make sense for the "convenience" version to be convenient.

Musa Over a year ago

@Pointy just tried it with $.ajax() and it worked, though I used the latest version of jQuery

user1464296 Over a year ago

I thought $.post() assumes json datatype if not explicitly set. I tried it and it worked. Strange, I thought json was set implicitly.

Pointy Over a year ago

@Musa hmm ... that's interesting; I'm not on 1.8 yet. I've got a hybrid system with JSON responses and I'm having to parse it myself. I'm not telling $.ajax() that the response type is JSON but I am setting the Content-Type (and I know I'm doing that because that's how my code tells the difference).

Pointy · Accepted Answer · 2012-09-03 22:52:46Z

1

The result of $.post() won't be parsed for you.

$.post(PROCESSORFILE, {"task": "getTableDupeFields", "table": table}, function(data) {
    data = $.parseJSON(data);
    $.each(data, function(key, value){
        $("#test-area").append(key+' is: '+value+'<br/>');
    });
    alert(data);
});

edit — oh and you can also pass a fourth parameter to $.post() but I'm not personally certain that passing "json" tells it to parse the result; it probably does.

answered Sep 3, 2012 at 22:52

Pointy

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