<script language='javascript'>
function ok(select){
if(select.options[select.selectedIndex].value!='#') {
window.open(select.options[select.selectedIndex].value,'_blank');
}
}
</script>
<select style="FONT-SIZE: 13px; WIDTH: 140px" onChange="ok(this)" name="select">
<option value="
http://www.sina.com.cn" >新浪</option>
<option value="
http://www.yahoo.com.cn" >雅虎</option>
<option value="
http://www.163.com" >网易</option>
</select>