Cannot checkbox values as array from $_POST?

Question

Possible Duplicate:
Get $_POST from multiple checkboxes

I'm a little new to web development and this is a problem (having completely stumped me) I feel has a simple solution, so I won't beat around the bush trying to figure it out myself. I will also focus on the most important bits.

I have some PHP code that is outputting a table, a form and a checkbox next to each row. Each one of the checkboxes looks like this:

<input type="checkbox" name="data_id" value="1">
<input type="checkbox" name="data_id" value="2">
<input type="checkbox" name="data_id" value="3">

As well as the submit button:

<input type='submit' name='Submit' value='Submit'/>

Standard form setup, nothing special.

I'd like to get the checked items in an array, however when I retrieve the data from the form using $_POST:

if($_POST['data_id'])
    {
        var_dump($_POST['data_id']); //returns string
        print_r($_POST['data_id']); //shows only one checkbox value
    };

What exactly am I doing wrong that the variable is not being returned an array?

How should I then call the var in PHP? – styke Oct 12 '12 at 14:26 — styke, Oct 12 '12 at 14:26

score 1 · Accepted Answer · answered Oct 12 '12 at 14:14

1

PHP's form-to-array syntax requires [] in the element name:

<input type="checkbox" name="data_id[]" value="1">
                                    ^^

answered Oct 12 '12 at 14:14

Marc B

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Fair does, but when I call $_POST['data_id'] I'm once again given a string? How should I call it in PHP correctly? – styke Oct 12 '12 at 14:18
it should come out as an array. do a `var_dump($_POST['data_id'])`. – Marc B Oct 12 '12 at 14:49
did you make sure to add the `[]` to your form field names and to reload the form? – Marc B Oct 12 '12 at 15:38
My bad, hadn't reloaded the form. Thank you! – styke Oct 12 '12 at 16:13

score 1 · Answer 2 · answered Oct 12 '12 at 14:14

When PHP parses data to $_POST/GET/REQUEST it only presents the data as an array if the field name ends in [] or [some_index] (otherwise it drops all but one of the values).

Rename the fields:

<input type="checkbox" name="data_id[]" value="1">
<input type="checkbox" name="data_id[]" value="2">
<input type="checkbox" name="data_id[]" value="3">

… or get the raw post data and parase it yourself. (I don't recommend this latter approach).

score 0 · Answer 3 · answered Oct 12 '12 at 14:16

0

Try

<input type="checkbox" name="data_id[]" value="1">
<input type="checkbox" name="data_id[]" value="2">
<input type="checkbox" name="data_id[]" value="3">

answered Oct 12 '12 at 14:16

Mohit Mehta

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Cannot checkbox values as array from $_POST?

3 Answers3