<script type="text/javascript">
function submit(){
if(document.getElementById("province").options[document.getElementById("province").selectedIndex].value==0){
alert("请选择省份！");
return false;
}else{
createXMLHttpRequest();
xmlHttp.open("post","index13.jsp",true);
xmlHttp.onreadystatechange=callback;
xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded;charset=UTF-8");
xmlHttp.send("province="+document.getElementById("province").options[document.getElementById("province").selectedIndex].value);
}
}
function callback(){
if(xmlHttp.readyState==4){
if(xmlHttp.status==200){
var city_string=xmlHttp.responseText;
var city_array=city_string.split(",");
while(document.getElementById("city").options.length>0){
document.getElementById("city").options.remove(0);
}
for(var j=0;j<city_array.length;j++){
var obj=document.getElementById("city");
obj.options=new Option(city_string,city_string);
alert(city_array);
}
} }
}
</script>
</head>
<body>
<center><h2>动态加载列表框</h2></center>
<center>省份：<select id="province" onchange="return submit()">
<option value="0">--选择省份--</option>
<option value="hn">河南</option>
<option value="gd">广东</option>
<option value="hb">湖南</option>
<option value="js">江苏</option>
</select>
城市：<select id="city"></select>
</center>
</body>
