How to get the values of check boxes in a group with PHP?

Question

I have a form where I added a group of check boxes like below:

<form action="next.php" method="get">
<input name="c1" value="1" type="checkbox">
<input name="c1" value="2" type="checkbox">
<input name="c1" value="3" type="checkbox">
<input name="c1" value="4" type="checkbox">
...
</form>

If I select the first and the 3rd check box, the URL looks good when I press the submit button, like

?c1=1&c1=3 [...]

but the $_GET array holds only the last value of c1. I know I could use the [] notation to get an array, but then the link looks like

?c1[]=1&c1[]=3 [...]

I saw sites that generate the URL without the [] and still manage to take all values into account. How do they do that ?

Thank you !

Not saying you can't do it, but PHP uses the array notation. Just how it is. — Jason McCreary
– Jason McCreary, Commented Nov 17, 2011 at 20:44

Marc B · Accepted Answer · 2011-11-17 20:43:24Z

2

PHP requires you to use a pseudo-array notation if you want to use the same fieldname for multiple different form elements:

<input type="checkbox" name="c1[]" ... />
<input type="checkbox" name="c1[]" ... />
<input type="checkbox" name="c1[]" ... />
etc...

The [] tells PHP to treat c1 as an array, and keep all of the submitted values. Without [], PHP will simply overwrite each previous c1 value with the new one, until the form's done processing.

Sites which don't use the [] notation do the form processing themselves, retrieving the query string from $_SERVER['QUERY_STRING'] and then parse it themselves.

answered Nov 17, 2011 at 20:43

Marc B

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BudwiseЯ · Accepted Answer · 2011-11-17 20:43:46Z

0

Use have to use this:

<input name="c1[]" value="1" type="checkbox">
<input name="c1[]" value="2" type="checkbox">
<input name="c1[]" value="3" type="checkbox">
<input name="c1[]" value="4" type="checkbox">

answered Nov 17, 2011 at 20:43

BudwiseЯ

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Lance Kidwell · Accepted Answer · 2011-11-17 21:45:15Z

0

You can still access the entire querystring. You can parse the querystring into parts like so:

$qs = explode("&",$_SERVER['QUERY_STRING']);

foreach ($qs as $part) {
    if (strpos($part,"c1") !== false) {
        $split = strpos($part,"=");
        $values[] = substr($part, $split + 1);
    }
}

var_dump($values);

If your querystring looks like this: ?c1=1&c1=3 the code above leaves you with a result like this:

array(2) { 
    [0]=> string(1) "1" 
    [1]=> string(1) "3" 
}

answered Nov 17, 2011 at 21:45

Lance Kidwell

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