Validating Select Drop Down Array in PHP - php

Question

I have the following to generate a state drop down on a form:
$states = array('State', 'Alabama', 'Alaska', 'Arizona', 'Arkansas');
echo "<select name='choose_state'>\n";
foreach ($states as $key => $state)
{echo "<option value='$key'>$state</option>\n";}
echo "</select>";
How would I go about making sure a user
1) only selects one of the options in the array
2) doesn't select the default value? ([0]=> string(5) "State")
edit: validate in php, this is for a form collecting user information before posting to a db
I tried using in_array and got stuck trying to exclude the default value

Answer 1

I think you're missing some checks. You should never rely on what is exacly posted, and always perform thorough checking:
$chosen_state = null;
if (array_key_exists('choose_state', $_POST))
{
$choose_state = $_POST['choose_state'];
if (array_key_exists($choose_state, $states) && $choose_state > 0)
{
// Value does actually exist in array and is not item 0.
$chosen_state = $states[$chose_state]);
}
}

Answer 2

Following example assumes that you're storing the key provided for the select in the var $state_key...
try this:
$max = sizeof($states) - 1; // this is the number of possible values that you have, minus the default
if($state_key != 0 && $state_key > 0 && $state_key < $max)
{
// do whatever here, you've got good data at this point
}
This also assumes that your default value is always key #0 (first in the array), by the way.

Answer 3

Validating form submit in php:
When you submit form in php, Select input type returns selected value in post. So you can do something like:
$selectedindex = $_POST["choose_state"];
if($selectedindex == 0)
{
echo "Default item has been selected";
}
else{
echo "Other than default item has been selected ";
//you can do further validation here for selected item
//is in between 0 and 5 if you need to do so
}