How to submit a form upon selection of an option?

How to submit a form upon selection of an option?

Is there a simple way to use a drop down select menu as a submit button as
well? I'd prefer to not have an <input type="submit" name="submit">, just
for the form to auto-submit upon selection of an option? Javascript,
jquery, php, css and pure HTML answers all work for me.
<form name="order" action="" method="get">
<select type="submit" name="carlist">
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>
</form>