submit form onChange doesn't work

Question

Any ideas why this wouldn't work? (empty action to submit to current page)

    <form action="" method="post" onchange="this.form.submit();">
        <span>Show by page</span>
        <select id="catfilternumber" name="lpp">
            <option value="6">6</option>
            <option value="12">12</option>
            <option value="24">24</option>
        </select>
    </form>

Answer 1

your onchange must be on select not on form