Undefined index & Invalid argument supplied for foreach() - php

Question

I am struggling with generating an output if none of the check boxes are selected from the code below.
HTML - Form
<label>Item 1:</label><input type="checkbox" name="selected[]" value="Item 1"/>
<label>Item 2:</label><input type="checkbox" name="selected[]" value="Item 2"/>
<label>Item 3:</label><input type="checkbox" name="selected[]" value="Item 3"/>
PHP Code
<?php
foreach ($_REQUEST['selected'] as $key => $selected) {
echo "$selected";
}
?>
The code outputs the correct value when selected, but generates the "Undefined index: selected in..." & "Invalid argument supplied for foreach():"
Can anyone point me in the right direction?
Thank you

Answer 1

You need to check the value is set before using it:
<?php
//$_REQUEST['selected'] is set and is array
if(isset($_REQUEST['selected']) && is_array($_REQUEST['selected'])){
//Loop it
foreach ($_REQUEST['selected'] as $key=>$selected) {
echo htmlspecialchars($selected);
}
}
?>
With Undefined index: extra that could be some other error, but you think it is this. any ways if you see an Undefined index warning that means your trying to access an array key that is undefined e.g not set.
FYI: Note that $_REQUEST will accept from $_GET and $_POST, if you are not expecting that value to be set from either, it would be better tobe more specific, so if you use POST in your form then use $_POST['selected']