選中後跳轉

<script type="text/javascript">
<!--
function mm_jumpmenu(targ, selobj, restore) { //v3.0
alert(selobj.selectedindex);
eval(targ + ".location='" + selobj.options[selobj.selectedindex].value + "'");
if (restore) { //selected=true
selobj.selectedindex = restore;
} else {
selobj.selectedindex = 0;
}
}
//-->
</script>
<form name="form1" id="form1">
<select name="menu1" onchange="mm_jumpmenu('parent',this,0)">
<option value="http://www.baidu.com">baidu</option>
<option value="http://www.sohu.com">sohu</option>
</select>
</form>
<script language="javascript">
function mm_jumpmenu(targ,selobj,restore){ //v3.0
window.open(selobj.value);
if (restore) selobj.selectedindex=0;
<select name="menu1" onchange="mm_jumpmenu('parent',this,0)">
<option value="http://www.21cn.com">21cn</option>
<option value="http://www.163.com">163</option>
</select>