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Javascript調(diào)用XML制作連動下拉列表框

更新時間：2006年06月25日 00:00:00 作者：

傳統(tǒng)的HTML頁面中連動下拉框采用了兩種方法：
1）直接將下拉框中的內(nèi)容hardcode于html的javascript中，調(diào)用javascript函數(shù)循環(huán)寫入下拉框中。這種方法不適用于下拉框內(nèi)容經(jīng)常改變的情況。因?yàn)閿?shù)據(jù)源和javascript程序?qū)懰涝谕豁撁妗?/FONT>

<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("徐匯區(qū)","01","001");
subcat[1] = new Array("嘉定區(qū)","01","002");
subcat[2] = new Array("黃浦區(qū)","01","003");
subcat[3] = new Array("南昌市","02","004");
subcat[4] = new Array("九江市","02","005");
subcat[5] = new Array("上饒市","02","006");

onecount=6;

function changelocation(locationid)
{
document.myform.smalllocation.length = 0;

var locationid=locationid;
var i;
document.myform.smalllocation.options[0] = new Option('====所有地區(qū)====','');
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="">==所有地區(qū)==</option>
</select>
</form>
<script LANGUAGE="javascript">

</script>
</body>
</html>

2）javascript 直接讀取數(shù)據(jù)庫，取數(shù)據(jù)庫中的記錄寫入javascript中，然后和第一種方法一樣，調(diào)用javascript函數(shù)循環(huán)寫入下拉框中。此方法將數(shù)據(jù)源與javascript分開，但,公開數(shù)據(jù)庫的連接，從安全角度說，沒有多少實(shí)用價(jià)值。

我的方法是將下拉框中的數(shù)據(jù)放在XML文件中，用javascript讀XML文件，取得下拉框中的內(nèi)容。

HTML 文件如下：

<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>

<title>在HTML中調(diào)用XML數(shù)據(jù)</title>
</head>
<body bgcolor="#FFFFFF">
<FORM NAME="frm">
類型<SELECT NAME="mainclass" OnChange='setsubclass(this[selectedIndex].text)'></SELECT>
<option selected value="" ></option>
子類<SELECT NAME="subclass"></SELECT>
</form>
</body>
</html>

account.xml 如下：

<?xml version="1.0" encoding="gb2312"?>
<item>
<class display_name="未選定">
<subclass display_name="">Not Available</subclass>
</class>
<class display_name="推薦網(wǎng)站">
<subclass display_name="看上去很美">www.7say.com</subclass>
<subclass display_name="移動互聯(lián)">www.xj139.com</subclass>
<subclass display_name="眾信實(shí)業(yè)">www.xjzxsy.com</subclass>
</class>
<class display_name="門戶網(wǎng)站">
<subclass display_name="新浪">www.sina.com</subclass>
<subclass display_name="搜狐">www.sohu.com</subclass>
</class>
<class display_name="其它網(wǎng)站">
<subclass display_name="藍(lán)色理想">www.blueidea.com</subclass>
</class>
</item>