Sending array from javascript to php not working correctly

Question

I'm creating an array on the jquery side this way. The array is an array of arrays where each element is an array that looks like [jskey, jsvalue].

    var jsarray = [];
//  jsarray.push([jskey, jsvalue]);
    jsarray.push([1, 123]);
    jsarray.push([2, 98]);
    jsarray.push([3, 107]);
    jsarray.push([4, 34]);

I then add the array to an element of a form before it's submitted

$('#myform input[name=jsvalues]').val(jsarray);

On the php side, I'm expecting to receive an array of array, but all I get when I do a print_r() or var_dump() is a string that looks like this

string() "1,123,2,98,3,107,4,34"

You're still working with HTTP here. Your form input can only contain some text string, not arbitrarily structured objects. JavaScript or jQuery was nice enough to try to serialize that array into a string of text somehow, it could've just yelled at you. Consider JSON-encoding the array and decoding it in PHP, or simply working with it as is, as you can easily turn that string back into an array with a line or two of PHP code. — Dan Grossman
– Dan Grossman, Commented Feb 2, 2011 at 0:23

Quentin · Accepted Answer · 2011-02-02 00:23:08Z

5

Attribute values are strings. When you convert an array to a string, you get each element in that array converted to a string and separated by commas (unless you override the toString() method (hint: don't)).

I suggest converting the array to JSON and then assigning that to the form control. You can then parse the JSON in PHP.

http://json.org has links (at the bottom) to PHP and JS implementations of JSON serializers / deserializers.

answered Feb 2, 2011 at 0:23

Quentin

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Pierre · Accepted Answer · 2011-02-02 00:43:48Z

2

David Dorward gave a really good solution. To clarify a little bit, when you assign a complex object (like an array) to the attribute of a HTML element (that's what jQuery does when you call val()), the object is converted into a string (by calling the toString method on the object).

An array has a toString method that does exactly what you are experiencing: a list of the values inside the array separated by commas:

[1, [2, 3]].toString(); // returns "1,2,3"

To transmit complex objets, you can use JSON (JavaScript Object Notation) which is native in JS:

$('#myform input[name=jsvalues]').val(JSON.stringify(jsarray));

On the server side, PHP 5 has a really fast JSON API:

$jsvalues = json_decode($_POST['jsvalues']);

edited Feb 2, 2011 at 0:43

answered Feb 2, 2011 at 0:37

Pierre

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Dan Grossman · Accepted Answer · 2011-02-02 00:26:55Z

0

You could convert that string back into an array of arrays, assuming they were all pairs:

$arr = explode(",", $_POST['jsvalues']);
$jsvalues = array();
for ($i = 0; $i < count($arr); $i += 2) {
    $jsvalues[] = array($arr[$i], $arr[$i + 1]);
}

answered Feb 2, 2011 at 0:26

Dan Grossman

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