Question - A simple way to get dropdown menu output into a PHP variable?

[foxystoat]

I’m trying to get the output of a dropdown menu into a php variable so I can use it to do queries etc.

The following code does work, but the div tags are also saved in the variable. Is there another way of doing it without the div tags? Maybe using _GET.

Ideally I would like minimal javascript like in my example instead of an external chunk of javascript so I can easily add more dropdown menus in the future.

<select name='trade' onchange="document.getElementById('extra').innerHTML = this.value;">
   <option value='item1'>item1</option>
   <option value='item2'>item2</option>
   <option value='item3'>item3</option>
   <option value='item4'>item4</option>
</select>

<?php

$extra = '<div id="extra"></div>';

echo $extra

?>