下拉菜单如果选了其它,就出现文本框让用户自己填写该怎么写代码啊
<html><head>
<title>下拉列表联动</title>
<script language="javascript">
function selCity_Change(CityName)
{
this.selArea.options.length=0;
for(var i=0;i<this.selTown.length;i++)
{
var iTown=this.selTown[i].value;
var iAry=iTown.split('|');
if(iAry[0]==CityName)
this.selArea.add(new Option(iAry[1],iAry[1]));
}
}
</script>
</head>
<body>
请先选择
<select name="selCity" onChange="selCity_Change(this.options[this.selectedIndex].value);" >
<option value="上城">上城</option>
<option value="下城">下城</option>
</select>
请选择
<select name="selArea">
</select>
<input type="hidden" name="selTown" value="上城|望江">
<input type="hidden" name="selTown" value="上城|南星桥">
<input type="hidden" name="selTown" value="上城|小营">
<input type="hidden" name="selTown" value="上城|吴山">
<input type="hidden" name="selTown" value="上城|近江">
<input type="hidden" name="selTown" value="上城|清河坊">
<input type="hidden" name="selTown" value="上城|美政">
<input type="hidden" name="selTown" value="上城|万松岭">
<input type="hidden" name="selTown" value="上城|官巷口">
<input type="hidden" name="selTown" value="上城|复兴">
<input type="hidden" name="selTown" value="上城|章家桥">
<input type="hidden" name="selTown" value="上城|城站">
<input type="hidden" name="selTown" value="上城|天水">
<input type="hidden" name="selTown" value="上城|武林门">
<input type="hidden" name="selTown" value="上城|其它">
<input type="hidden" name="selTown" value="下城|长兴">
<input type="hidden" name="selTown" value="下城|朝晖">
<input type="hidden" name="selTown" value="下城|文晖">
<input type="hidden" name="selTown" value="下城|潮鸣">
<input type="hidden" name="selTown" value="下城|东新园">
<input type="hidden" name="selTown" value="下城|长木桥">
<input type="hidden" name="selTown" value="下城|石桥">
<input type="hidden" name="selTown" value="下城|和平">
<input type="hidden" name="selTown" value="下城|德胜">
<input type="hidden" name="selTown" value="下城|董家">
<input type="hidden" name="selTown" value="下城|其它">
</body>
</html>
如果用户选了其它,就出现文本框让用户自己填,怎么实现啊,
