onChange event Question

<select name="country">
            <option>india</option>
            <option>usa</option>
            <option>pak</option>
            <option>england</option>
            <option>aus</option>
            <option>newzeland</option>
            <option>rsa</option>
            <option>srilanka</option>
            <option>west indies</option>
          </select>
        </div>
      </label></td>
    </tr>
    <tr>
      <td><div align="right" class="style4">City/Area</div></td>
      <td>:</td>
      <td><label>
        <div align="left">
          <label>
          <select name="area" size="1" multiple="multiple" id="area">
          </select>
          </label>

HTML:

i have a list of countries in one select box.when i selecting a perticular country,depending on country, how to change a cities/area list box automatically.suppose when i selected a usa then i want to show only usa cities.like england....etc..

 

You can use (or take a look) this Chained Select Menu