Code<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<script language="JavaScript" type="text/javascript">
//定义了城市的二维数组，里面的顺序跟省份的顺序是相同的。通过selectedIndex获得省份的下标值来得到相应的城市数组
var city=[
["北京","天津","上海","重庆"],
["南京","苏州","南通","常州"],
["福州","福安","龙岩","南平"],
["广州","潮阳","潮州","澄海"],
["兰州","白银","定西","敦煌"]
];
function getCity(){
//获得省份下拉框的对象
var sltProvince=document.form1.province;
//获得城市下拉框的对象
var sltCity=document.form1.city;
//得到对应省份的城市数组
var provinceCity=city[sltProvince.selectedIndex - 1];
//清空城市下拉框，仅留提示选项
sltCity.length=1;
//将城市数组中的值填充到城市下拉框中
for(var i=0;i<provinceCity.length;i++){
sltCity[i+1]=new Option(provinceCity[i],provinceCity[i]);
}
}
</script>
</HEAD>
<BODY>
<FORM METHOD=POST ACTION="" name="form1">
<SELECT NAME="province" onChange="getCity()">
<OPTION VALUE="0">请选择所在省份 </OPTION>
<OPTION VALUE="直辖市">直辖市 </OPTION>
<OPTION VALUE="江苏省">江苏省 </OPTION>
<OPTION VALUE="福建省">福建省 </OPTION>
<OPTION VALUE="广东省">广东省 </OPTION>
<OPTION VALUE="甘肃省">甘肃省 </OPTION>
</SELECT>
<SELECT NAME="city">
<OPTION VALUE="0">请选择所在城市 </OPTION>
</SELECT>
</FORM>
</BODY>
</HTML>
