1）直接将下拉框中的内容hardcode于html的javascript中，挪用Javascript函数轮回写入下拉框中。这类要领不适用于下拉框内容常常转变的状况。由于数据源和javascript顺序写死在统一页面。
<html>
<head>
<title>List</title>
<meta http-equiv="Content-Type" content="text/html; c
harset=gb2312">
<script LANGUAGE="javascript">
<!--
var onecount;
onecount=0;
subcat = new Array();
subcat[0] = new Array("徐汇区","01","001");
subcat[1] = new Array("嘉定区","01","002");
subcat[2] = new Array("黄浦区","01","003");
subcat[3] = new Array("南昌市","02","004");
subcat[4] = new Array("九江市","02","005");
subcat[5] = new Array("上饶市","02","006");
onecount=6;
function changelocation(locationid)
{
document.myform.smalllocation.length = 0;
var locationid=locationid;
var i;
document.myform.smalllocation.options[0] = new Option('====一切区域====','');
for (i=0;i <onecount; i++)
{
if (subcat[i][1] == locationid)
{
document.myform.smalllocation.options[document.myform.smalllocation.length]
= new Option(subcat[i][0], subcat[i][2]);
}
}
}
//-->
</script>
</head>
<body>
<form name="myform" method="post">
<select name="biglocation"
onChange="changelocation(document.myform.biglocation.options[document.myform.biglocation.selectedIndex].value)">
<option value="01" selected>上海</option>
<option value="02">江西</option>
</select>
<select name="smalllocation">
<option selected value="">==一切区域==</option>
</select>
</form>
<script LANGUAGE="javascript">
<!--
changelocation(document.myform.biglocation.options[document.myform.biglocation.selectedIndex].value);
//-->
</script>
</body>
</html>
2）javascript 直接读取数据库，取数据库中的纪录写入javascript中，然后和第一种要领一样，挪用javascript函数轮回写入下拉框中。此要领将数据源与javascript离开，但,公然数据库的衔接，从平安角度说，没有若干实用价值。
我的要领是将下拉框中的数据放在xml文件中，用javascript读XML文件，获得下拉框中的内容。
HTML 文件以下：
<!-- myfile.html -->
<html>
<head>
<script language="JavaScript" for="window" event="onload">
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
var i=0;
var j=0;
var subclass_name="";
loadXML();
function loadXML(){
xmlDoc.async="false";
xmlDoc.load("account.xml");
xmlObj=xmlDoc.documentElement;
nodes = xmlDoc.documentElement.childNodes;
document.frm.mainclass.options.length = 0;
document.frm.subclass.options.length = 0;
for (i=0;i<xmlObj.childNodes.length;i++){
labels=xmlObj.childNodes(i).getAttribute("display_name");
values=xmlObj.childNodes(i).text;
document.frm.mainclass.add(document.createElement("OPTION"));
document.frm.mainclass.options[i].text=labels;
document.frm.mainclass.options[i].value=values;
}
}
</script>
<script language="JavaScript" >
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
var i=0;
var j=0;
function deleteOption() {
}
function setsubclass(main){
var is_selected="N";
if (document.frm.subclass.options.length!=0) {
for (i=0;i<=document.frm.subclass.options.length;i++)
document.frm.subclass.options[i]=null ;
}
//反复才有用
if (document.frm.subclass.options.length!=0) {
for (i=0;i<=document.frm.subclass.options.length;i++){
document.frm.subclass.options[i]=null ;
document.frm.subclass.options.remove(i);
}
}
for (i=0;i<xmlObj.childNodes.length;i++){
var values="";
var lables="";
if (is_selected=="Y") return;
labels=xmlObj.childNodes(i).getAttribute("display_name");
values=xmlObj.childNodes(i).text;
//alert(labels+ " | "+main);
if (labels==main){
is_selected="Y";
for (j=0;j<xmlObj.childNodes(i).childNodes.length;j++){
//subclass_name="document.frm.subclass";
labels=xmlObj.childNodes(i).childNodes(j).getAttribute("display_name");
values=xmlObj.childNodes(i).childNodes(j).text;
//alert(values);
document.frm.subclass.add(document.createElement("OPTION"));
document.frm.subclass.options[j].text=labels;
document.frm.subclass.options[j].value=values;
}
}
}
}
</script>
<title>在HTML中挪用XML数据</title>
</head>
<body bgcolor="#FFFFFF">
<FORM NAME="frm">
范例<SELECT NAME="mainclass" OnChange='setsubclass(this[selectedIndex].text)'></SELECT>
<option selected value="" ></option>
子类<SELECT NAME="subclass"></SELECT>
</form>
</body>
</html>
account.xml 以下：
<?xml version="1.0" encoding="GB2312"?>
<item>
<class display_name="未选定">
<subclass display_name="">Not Available</subclass>
</class>
<class display_name="95788主叫卡">
<subclass display_name="1152069589-1152069638">dangdang1</subclass>
<subclass display_name="1152081031-1152081080">dangdang2</subclass>
<subclass display_name="1152547201-1105254750">dangdang3</subclass>
<subclass display_name="1152548401-1152548700">dangdang4</subclass>
<subclass display_name="1152548701-1152549000">dangdang5</subclass>
<subclass display_name="1156000001-1156010000">dangdang6</subclass>
</class>
<class display_name="网上注册">
<subclass display_name="1152000001-1152001000">zhuce_user1</subclass>
<subclass display_name="1151001000-1151005000">zhuce_user2</subclass>
</class>
<class display_name="通信">
<subclass display_name="1156030001-1156080000">tongxun</subclass>
</class>
</item>
此要领将数据源与javascript顺序离开，合适常常变化的数据源。xmlDoc.load中能够直接挪用URL参数,读取长途XML，完成松耦合。以上应用在IE6.0中经由过程。不足之处是在去除下拉框列表内容时须要
反复实行删除操纵，不然会有显著的bug.愿望有读者能给斧正。
以上就是Javascript 挪用XML制造连动下拉框代码实例详解的内容，更多相关内容请关注ki4网（www.ki4.cn）！
