<select onChange=javascript:window.navigate(this.options[this.selectedIndex].value);>
<option></option>
<option value=http://www.microsoft.com>微软</option>
</select>
<option></option>
<option value=http://www.microsoft.com>微软</option>
</select>
<option></option>
<option value=http://www.microsoft.com>微软</option>
</select>
<option></option>
<option value=http://www.microsoft.com>微软</option>
</select>