I'm using the Kohana PHP framework, not very familiar with Kohana and only a novice with PHP and javascript. I'm working on a project where I have a form::dropdown filled with a list of categories and another dropdown (second one using multiple selections) which needs to be filled dynamically based on which of my categories in the first dropdown is selected. So I know I need an 'onchange' function, but not sure how to include it. And if my javascript function should go anywhere specifically. Below is my form::dropdown definition for the first dropdown. Any help would be appreciated. Thanks.
<?=form::dropdown(array('name' => 'category_id', 'class' => 'input-select'), $categories, $members)?>