关于下拉菜单和onchange的问题，请教各位！解决了马上结贴送分!

window.Form1.Select2.innerHTML="" /清空
xiang=new Option();
xiang.text=""
xiang.value=""
window.Form1.Select2.add(xiang); /填加新内容

解决方案 »

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有两种方法：
1、用 iframe 做
   后面两个选择框做成iframe 用数据库查询2、用javascript
兄弟，你有救了，我网站上有演示
http://www.gnzx.com:8088/005.htm<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head><body></body><BODY>
<SELECT NAME="s1"><option>需要JavaScript才能正确显示</SELECT>
<SELECT NAME="s2"></SELECT>
<SELECT NAME="s3"></SELECT>
<SELECT NAME="s4"></SELECT>
<SCRIPT LANGUAGE="JavaScript">

</SCRIPT>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title></title>
</head><body>
<SELECT name="Continet" onchange="ChgContinet()">
<OPTION SELECTED value="">－请选择洲－</OPTION>
<OPTION value="AMERCIA"> 美洲</OPTION>
<OPTION value="ASIA"> 亚洲</OPTION>
</SELECT>
<SELECT name="Country" onchange="ChgCountry()">
<OPTION SELECTED>－请选择国家－</OPTION>
</SELECT>
<SELECT name="City">
<OPTION SELECTED>－请选择城市－</OPTION>
</SELECT>
</body>
</html>
<script language="JavaScript" type="text/JavaScript">
var ChinaCity = new Array("安徽","澳门","北京","重庆","福建","甘肃","广东","广西","贵州","海南","河北","黑龙江","河南","湖北","湖南","江苏","江西","吉林","辽宁","内蒙古","宁夏","青海","陕西","山东","山西","上海","四川","台湾","天津","新疆","香港","西藏","云南","浙江");
var UsCity = new Array("城市一","城市二","城市三","城市四");
var CanCity = new Array("城市A","城市B","城市C","城市D");
var JpCity = new Array("城市a","城市b","城市c","城市d");
var AmCountry = new Array( "美国","加拿大" );
var AmCounValue = new Array( "US","CAN" );
var AsCountry = new Array( "中国","日本" );
var AsCounValue = new Array( "CHINA", "JP" );
function ChgContinet() {
var SelConValue = "";
var SelSize = 0;
var SelField = window.Country;
var stCountry = new Array();
var stValue= new Array();
var NewOption;
for( var i = SelField.length - 1; i>=0; i-- ){
SelField.remove(i);
}
SelConValue = Continet.options[Continet.selectedIndex].value;
if( SelConValue == "AMERCIA" ) {
stCountry = AmCountry;
stValue = AmCounValue;
} else if ( SelConValue == "ASIA" ) {
stCountry = AsCountry;
stValue = AsCounValue;
} else if ( SelConValue == "" ) {
NewOption = document.createElement("OPTION")
NewOption.text = "－请选择国家－";
NewOption.value = "";
SelField.add(NewOption);
ChgCountry();
return;
}
SelSize = stCountry.length;
for(var i=0; i<SelSize; i++) {
NewOption = document.createElement("OPTION");
NewOption.text = stCountry[i];
NewOption.value = stValue[i];
SelField.add(NewOption);
}

ChgCountry();
}
function ChgCountry() {

var SelValue = "";
var SelSize = 0;
var RightSel = window.City;
var NewOption;
var stCity = new Array();
for(var i=RightSel.length-1; i>=0; i--){
RightSel.remove(i);
}
SelValue = Country.options[Country.selectedIndex].value;
if(SelValue == "CHINA") {
stCity = ChinaCity;
} else if(SelValue == "US") {
stCity = UsCity;
} else if(SelValue == "CAN") {
stCity = CanCity;
} else if(SelValue == "JP") {
stCity = JpCity;
} else if(SelValue == "") {
NewOption = document.createElement("OPTION");
NewOption.text = "－请选择城市－";
NewOption.value =
RightSel.add(NewOption);
return;
}
SelSize = stCity.length;
for(var i=0; i<SelSize; i++) {
NewOption = document.createElement("OPTION");
NewOption.text = stCity[i];
RightSel.add(NewOption);
}}
</script>
这是阿信写的。。多级连动。。http://fason.nease.net/code/form/select/multiple1.htm
<BODY>
<SELECT NAME="s1"><option>需要JavaScript才能正确显示</SELECT>
<SELECT NAME="s2"></SELECT>
<SELECT NAME="s3"></SELECT>
<SELECT NAME="s4"></SELECT>
<SCRIPT LANGUAGE="JavaScript">

</SCRIPT>
   <p align="right"><a href="http://fason.nease.net">【阿信的小天地】</a></p>
</BODY>
你这个问题，我以前碰到过。为了解决它，花了我一整天的时间，当时也是不太熟悉SCRIPT。现在我愿意拿出来和你一起分享它。下面的代码都调试过了，粘贴即可。<html>
<Script LANGUAGE ="JavaScript" TYPE ="text/javascript" >

</Script><body >洲名<SELECT size=4 name=conti onChange='changeContinent();'>
<OPTION value='' >全部</OPTION>
<OPTION value='美洲' >美洲</OPTION>
<OPTION value='欧洲' >欧洲</OPTION>
</SELECT>
</SELECT>
国家<SELECT size=4 name="countries" onChange='changeCountry();'>
<OPTION value='' >全部</OPTION>
</SELECT>城市<SELECT size=4 name="cities">
<OPTION value='' >全部</OPTION>
</SELECT>
</body>
</html>
<form name=form1>
<select name=province onchange="cityName(this.selectedIndex)">
  <option value="">请选择省名</option>
</select><select name=city>
  <option value="">请选择城名</option>
</select>
</form><script language=javascript>var provinceName = ["美洲", "欧洲", "安徽", "江西"];
var city1 = ["美国", "加拿大"];
var city2 = ["法国", "英国"];
var city3 = ["合肥", "翕县", "黄山", "祁门", "休宁"];
var city4 = ["南昌", "九江", "赣州", "上饶", "新余", "景德镇"];
function province()
{    var e = document.form1.province;
    for (var i=0; i<provinceName.length; i++)
       e.options.add(new Option(provinceName[i], provinceName[i]));
}
function cityName(n)
{
    var e = document.form1.city;
    e.options.length = 1;
    if (n == 0) return;
    var a = eval("city"+ n); //得到城市的数组名
    for (var i=0; i<a.length; i++) e.options.add(new Option(a[i], a[i]));
}
window.attachEvent("onload", province);  //初始时给省名下拉框赋内容
</script>