make the drop down menu show from another buttons click

Question

If I click on my a href button how do I make the drop down menu show?

<a href="#" onclick"makeIDCarsMenuShow()" >my button</a>
<select name="cars" id="cars">
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="fiat" selected="selected">Fiat</option>
<option value="audi">Audi</option>
</select>


<script>
  function makeIDCarsMenuShow(){
    $('#cars').trigger('click');
  }
</script>

Answer 1

try this

 <a href="#" onclick"return makeIDCarsMenuShow()" >my button</a>
 <select name="cars" id="cars">
   <option value="volvo">Volvo</option>
   <option value="saab">Saab</option>
   <option value="fiat" selected="selected">Fiat</option>
   <option value="audi">Audi</option>
 </select>


<script>
   function makeIDCarsMenuShow(){
    $('#cars').click();
    return false;
   }
</script>