<select name="a" OnChange="window.location=this.value">
<option value="a.html">aaaa</option>
<option value="b.html">bbbb</option>
<option value="c.html">cccc</option>
<option value="d.html">dddd</option>
<option value="e.html">eeee</option>
</select>
<option value="a.html">aaaa</option>
<option value="b.html">bbbb</option>
<option value="c.html">cccc</option>
<option value="d.html">dddd</option>
<option value="e.html">eeee</option>
</select>
<select name="a">
<option value="a.html">aaaa</option>
<option value="b.html">bbbb</option>
<option value="c.html">cccc</option>
<option value="d.html">dddd</option>
<option value="e.html">eeee</option>
</select>
<input type="button" name="Submit" value="Go"
onclick="location.href=document.all.a.options[document.all.a.options.selectedIndex].value">
</form>
<script>
function