JavaScript XML实现两级级联下拉列表-丞旭猿

1.创建测试XML文件:select.xml

实现代码如下：

<?xml version=”1.0″ encoding=”GBK”?> 
<select> 
<province id=”sx”> 
陕西 
<city id=”xa”>西安</city> 
<city id=”bj”>宝鸡</city> 
<city id=”ak”>安康</city> 
</province> 
<province id=”js”> 
江苏 
<city id=”nj”>南京</city> 
<city id=”xz”>徐州</city> 
</province> 
<province id=”sh”> 
上海 
</province> 
</select> 

2.创建HTML页面:select.html

实现代码如下：

<body> 
</body> 
<script>… 
/**//** 
* @description 二级级联下拉 
* @author BluesLee 
* @lastModif BluesLee 
* @createDate 2007-10-13 
* @modifDate 2007-10-15 
* @version 1.0 
*/ 
SelectLevel.prototype.xml; 
SelectLevel.prototype.provinces; 
SelectLevel.prototype.parentName=”province”;//父节点名称 
SelectLevel.prototype.childName=”city”;//子节点名称 
SelectLevel.prototype.keyName=”id”;//属性 
/**//** 
* 对象SelectLevel的构造器 
* @author BluesLee 
* @lastModif BluesLee 
* @createDate 2007-10-13 
* @modifDate 2007-10-15 
* @version 1.0 
*/ 
function SelectLevel(parentName,childName,keyName)…{ 
if(parentName!=null && parentName!=””)…{ 
this.parentName=parentName; 
} 
if(childName!=null && childName!=””)…{ 
this.childName=childName; 
} 
if(keyName!=null && keyName!=””)…{ 
this.keyName=keyName; 
} 
} 
/**//** 
* 加载xml文件 
* @author BluesLee 
* @lastModif BluesLee 
* @createDate 2007-10-13 
* @modifDate 2007-10-15 
* @version 1.0 
*/ 
SelectLevel.prototype.readXML=function(url)…{ 
var selectXML; 
//如果它受支持，采用标准的2级DOM技术 
if(document.implementation && document.implementation.createDocument)…{ 
//创建新的Document对象 
selectXML=document.implementation.createDocument(“”,””,null); 
//设置装载完毕时触发事件 
selectXML.onload=function()…{ 
alert(“加载完成”); 
} 
selectXML.load(url); 
}else…{//IE浏览器创建Document对象 
selectXML=new ActiveXObject(“Microsoft.XMLDOM”); 
//设置onload 
selectXML.onreadystatechange=function()…{ 
if(selectXML.readyState==4)…{ 
alert(“加载完成”); 
} 
} 
selectXML.load(url); 
} 
this.xml=selectXML; 
} 
/**//** 
* 遍历xml 
* @author BluesLee 
* @lastModif BluesLee 
* @createDate 2007-10-13 
* @modifDate 2007-10-15 
* @version 1.0 
*/ 
SelectLevel.prototype.iteratorXML=function(node,level)…{ 
var n=node; 
if(n==null)…{ 
n=this.xml.documentElement; 
} 
if(level==null)…{ 
level=0; 
} 
if(n.nodeType==3)…{ 
for(var i=0;i<level;i++)…{ 
document.write(“-“); 
} 
document.write(n.data.trim()+”<br>”); 
}else…{ 
for(var m=n.firstChild;m!=null;m=m.nextSibling)…{ 
this.iteratorXML(m,level+1); 
} 
} 
} 
/**//** 
* 下拉联动 
* @author BluesLee 
* @lastModif BluesLee 
* @createDate 2007-10-13 
* @modifDate 2007-10-15 
* @version 1.0 
*/ 
SelectLevel.prototype.changeSelect=function()…{ 
var city=document.getElementById(this.childName); 
var province=document.getElementById(this.parentName); 
city.options.length=0; 
if(province.value==null || province.value==””)…{ 
city.options.length=1; 
city.options[0].text=”请选择…”; 
return; 
} 
var citys=this.provinces[this[province.value]].getElementsByTagName(this.childName); 
if(citys.length==0)…{ 
city.options.length=city.options.length+1; 
city.options[city.options.length-1].value=province.value; 
for(var i=0;i<province.options.length;i++)…{ 
if(province.options[i].selected)…{ 
city.options[city.options.length-1].text=province.options[i].text; 
return; 
} 
} 
return; 
} 
city.options.length=citys.length; 
for(var i=0;i<citys.length;i++)…{ 
city.options[i].value=citys[i].getAttribute(this.keyName); 
city.options[i].text=citys[i].firstChild.data.trim(); 
} 
} 
/**//** 
* 初始化下拉列表 
* @author BluesLee 
* @lastModif BluesLee 
* @createDate 2007-10-13 
* @modifDate 2007-10-15 
* @version 1.0 
*/ 
SelectLevel.prototype.init=function(parent,province,city)…{ 
this.provinces=this.xml.getElementsByTagName(this.parentName); 
var selectProvince=document.createElement(“select”); 
var selectCity=document.createElement(“select”); 
var obj=this; 
selectProvince.setAttribute(“name”,this.parentName); 
selectProvince.setAttribute(“id”,this.parentName); 
selectProvince.attachEvent(“onchange”,function()…{obj.changeSelect();}); 
selectProvince.options.length=this.provinces.length+1; 
selectProvince.options[0].text=”请选择…”; 
selectCity.setAttribute(“name”,this.childName); 
selectCity.setAttribute(“id”,this.childName); 
selectCity.options.length=1; 
selectCity.options[0].text=”请选择…”; 
for(var i=0;i<this.provinces.length;i++)…{ 
SelectLevel.prototype[this.provinces[i].getAttribute(this.keyName)]=i; 
selectProvince.options[i+1].value=this.provinces[i].getAttribute(this.keyName); 
selectProvince.options[i+1].text=this.provinces[i].firstChild.data.trim(); 
if(this.provinces[i].getAttribute(this.keyName)==province)…{ 
selectProvince.options[i+1].selected=true; 
var citys=this.provinces[i].getElementsByTagName(this.childName); 
selectCity.options.length=citys.length+1; 
for(var j=0;j<citys.length;j++)…{ 
selectCity.options[j+1].value=citys[j].getAttribute(this.keyName); 
selectCity.options[j+1].text=citys[j].firstChild.data.trim(); 
if(citys[j].getAttribute(this.keyName)==city)…{ 
selectCity.options[j+1].selected=true; 
} 
} 
} 
} 
parent.appendChild(selectProvince); 
parent.appendChild(selectCity); 
} 
String.prototype.trim=function()…{ 
return this.replace(/^s*/g,””).replace(/s*$/g,””); 
} 
//测试 
var newXML=new SelectLevel(); 
newXML.readXML(“select.xml”); 
//newXML.iteratorXML(null,-2); 
newXML.init(document.body,”sx”,”bj”); 
</script> 

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