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 !

Answer 1

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.