传统的HTML页面中连动下拉框采用了两种方法:1)直接将下拉框中的内容hardcode于html的javascript中,调用javascript函数循环写入下拉框中。这种方法不适用于下拉框内容经常改变的情况。因为数据源和javascript程序写死在同一页面。
<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('====所有地区====','');
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="">==所有地区==</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,取数据库中的记录写入javascript中,然后和第一种方法一样,调用javascript函数循环写入下拉框中。此方法将数据源与javascript分开,但,公开数据库的连接,从安全角度说,没有多少实用价值。
我的方法是将下拉框中的数据放在XML文件中,用javascript读XML文件,取得下拉框中的内容。
HTML 文件如下:
<!-- 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 ;
}
//重复才有效
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中调用XML数据</title>
</head>
<body bgcolor="#FFFFFF">
<FORM NAME="frm">
类型<SELECT NAME="mainclass" OnChange='setsubclass(this[selectedIndex].text)'></SELECT>
<option selected value="" ></option>
子类<SELECT NAME="subclass"></SELECT>
</form>
</body>
</html>
account.xml 如下:
<?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="通讯">
<subclass display_name="1156030001-1156080000">tongxun</subclass>
</class>
</item>
此方法将数据源与javascript程序分开,适合经常变化的数据源。xmlDoc.load中可以直接调用URL参数,读取远程XML,实现松耦合。以上应用在IE6.0中通过。不足之处是在去除下拉框列表内容时需要。
--------------------------------------------------------------------------------------[下面是第一种方法的asp 写法]
'取子分类于rs1
dim count
set rs1=server.createobject("adodb.recordset")
sql = "select * from jxkhzbzzfl order by zzfl_id asc"
rs1.open sql,conn,1,1
'-----------------------------------------
'将子分类记录写入数组subcat(子类名、父ID、子ID
'-----------------------------------------
%>
<script language = "JavaScript">
var onecount;
onecount=0;
subcat = new Array();
<%count = 0
do while not rs1.eof %>
subcat[<%=count%>] = new Array("<%= trim(rs1("zzfl_name"))%>","<%= trim(rs1("year"))%>","<%= trim(rs1("zzfl_id"))%>");
<%count = count + 1
rs1.movenext
loop
rs1.close
%>
//列出所有子分类于数组subcat中供后面使用
//var subcat = new Array();
//subcat[0] = new Array('10','1','=1')
//subcat[1] = new Array('10','2','=2')
//subcat[0][0]='10' //rs1("zfl_name")
//subcat[0][1]='1' //rs1("zzfl_id")
//subcat[0][2]='=1' //rs1("zfl_id")
//subcat[1][0]='10'
//subcat[1][1]='2'
//subcat[1][2]='=2'
//.....
onecount=<%=count%>;
function changelocation(locationid)
{
document.form.zzfl_id.length = 0;
var locationid=locationid;
var i;
for (i=0;i < onecount; i++)
{
if (subcat[i][1] == locationid)//
{
document.form.zzfl_id.options[document.form.zzfl_id.length] = new Option(subcat[i][0], subcat[i][2]);
//document.form.zzfl_id.length第一次为0,过出某大类的所有子类
}
}
}
// onchange="changelocation(this.options.selectIndex)"
//应该是onchange="changelocation(this.options.selectedIndex)"
//new option();应该是 new Option();//大写的O
//<select id="s">
//</select>
//var option = new Option( "abc", "2312" );
//document.all.s.options[0] = option;
//var option2 = new Option( "def", "2312" );
//document.all.s.options[1] = option2;
//Option是 select 中的选择项,str1 是页面中看到的描述,而str2是这一项的值,比如
//<option value="这里是str2">这里是str1</option>
//new option(); 一般用在动态生成选择项目
</script>
一级分类
<select name="my1" onChange="changelocation(document.form.my1.options[document.form.my1.selectedIndex].value)">
<option value="2008" <%if myear="2008" then %>selected<%end if%>>2008</option>
<option value="2009" <%if myear="2009" then %>selected<%end if%>>2009</option>
</select>
二级分类
<select name="zzfl_id">
<%
set rs2=server.createobject("ADODB.recordset")
rs2.open "select * from jxkhzbzzfl where year='" & myear & "'",conn,1,1
if rs2.eof then
else
do while not rs2.eof
if cstr(rs2("zzfl_id"))=cstr(mzzfl_id) then
%>
<option value="<%=rs2("zzfl_id")%>" selected><%=rs2("zzfl_name")%></option>
<%else%>
<option value="<%=rs2("zzfl_id")%>" ><%=rs2("zzfl_name")%></option>
<%end if
rs2.movenext
loop
rs2.close
set rs2=nothing
end if
%></select>