Checkboxes/Multiple Select Boxes in PHP

For the PHP newbie, checkboxes and/or multiple select listboxes can be baffling in the beginning. It’s actually not very hard at all, and is often one of the PHP newbie’s first experience with arrays.

The logic behind checkboxes and multiple select listboxes is identical. Because of this, we’ll get the HTML bit of it done for both:

A. Checkboxes
<input type=”checkbox” name=”foo[]” value=”1″>
<input type=”checkbox” name=”foo[]” value=”2″>
<input type=”checkbox” name=”foo[]” value=”3″>
(etc….)

B. Multiple Select Listboxes
<select name=”foo[]” size=”4″ multiple>
<option value=”apples”>Apples</option>
<option value=”oranges”>Oranges</option>
<option value=”pears”>Pears</option>
<option value=”grapes”>Grapes</option>
<option value=”mangos”>Mangos</option>
</select>

Getting the data out

Now we just have to write the PHP code that will be able to extract the data the user selected from the array we created ($foo[])

// check to be sure at least one option was selected
$foo = $_POST['foo'];
if (count($foo) > 0) {
// loop through the array
for ($i=0;$i<count($foo);$i++) {

// do something - this can be a SQL query,
// echoing data to the browser, or whatever
echo "<li>$foo[$i] \n";

} // end "for" loop

} // endif

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