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javascript 三级下拉选择菜单Levels对象

　　发布时间：2023-09-05 03:28:48　

标签：javascript, , ,下拉选择,菜单

JavaScript：

<script type="text/javascript">
var level1 = ["Beijing", "GuangZhou", "ShangHai"];
var level2 = [["ZhaoYang", "TianTan", "GuGong"], ["Tianhe", "Panyu"], ["PuDong", "PuXi"]];
var level3 = [[["TianShan", "HuangShan"], ["TianTan1", "TianTan2"], ["GuGong1", "GuGong2", "GuGong3", "GuGong4"]], [["TianHe1", "TianHe2"], ["PanYu1", "PanYu2"]], [["PuDong1", "PuDong2"], ["PuXi1", "PuXi2"]]];
var Levels = {
fL: null,//用存储各级select的DOM引用
sL: null,
tL: null,
l1: null,
l2: null,
l3: null,
$: function(id){
return (typeof id == "object") ? id : document.getElementById(id);
},
init: function(fID, sID, tID, l1, l2, l3){
this.fL = this.$(fID);
this.sL = this.$(sID);
this.tL = this.$(tID);
this.l1 = l1;
this.l2 = l2;
this.l3 = l3;
this.fL.options.add(new Option("Select",-1));//给一级菜单添加一个“select”标志
for (var i = 0; i < l1.length; i++) {
var item = new Option(l1[i], i);
this.fL.options.add(item);
}
this.doLev2(); //调用doLev2函数，处理二级菜单
this.doLev3(); //调用doLev3函数，处理 * 菜单
},
removeSTL: function(){ //用于删除第二、 * 的菜单项
this.sL.options.length = 0;
this.tL.options.length = 0;
},
removeTL: function(){ //用于删除第 * 的菜单项
this.tL.options.length = 0;
},
doLev2: function(){ //处理二级菜单
var that = this;
this.fL.onchange = function(){
that.removeSTL(); //删除旧second的select
if (that.fL.selectedIndex == 0) {
that.removeSTL(); // //删除旧second的select
}
else {
that.sL.options.add(new Option("Select", -1)); //给二级菜单添加一个“select”标志
//获取第二级所需的数组
var items = that.l2[that.fL.selectedIndex - 1];
for (var i = 0; i < items.length; i++) { //添加第二级的新select项
var item = new Option(items[i], i);
that.sL.options.add(item);
}
}
}
},
doLev3: function(){ //处理 * 菜单
var that = this;
this.sL.onchange = function(){
that.removeTL(); //删除旧third的select
if (that.sL.selectedIndex == 0) {
that.removeTL(); //删除旧third的select
}
else {
that.tL.options.add(new Option("Select", -1)); //给 * 菜单添加一个“select”标志
//获取第 * 所需的数组
var items = that.l3[that.fL.selectedIndex - 1][that.sL.selectedIndex - 1];
for (var i = 0; i < items.length; i++) { //添加第 * 的新select项
var item = new Option(items[i], i);
that.tL.options.add(item);
}
}
}
}
}
onload = function(){
Levels.init("first", "second", "third", level1,level2,level3); //调用Levels的init方法
}
</script>

HTML：

<form>
<select id="first">
</select>
<select id="second">
</select>
<select id="third">
</select>
</form>

演示代码：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <title>Untitled Document</title> <script type="text/javascript"> var level1 = ["Beijing", "GuangZhou", "ShangHai"]; var level2 = [["ZhaoYang", "TianTan", "GuGong"], ["Tianhe", "Panyu"], ["PuDong", "PuXi"]]; var level3 = [[["TianShan", "HuangShan"], ["TianTan1", "TianTan2"], ["GuGong1", "GuGong2", "GuGong3", "GuGong4"]], [["TianHe1", "TianHe2"], ["PanYu1", "PanYu2"]], [["PuDong1", "PuDong2"], ["PuXi1", "PuXi2"]]]; var Levels = { fL: null,//用存储各级select的DOM引用 sL: null, tL: null, l1: null, l2: null, l3: null, $: function(id){ return (typeof id == "object") ? id : document.getElementById(id); }, init: function(fID, sID, tID, l1, l2, l3){ this.fL = this.$(fID); this.sL = this.$(sID); this.tL = this.$(tID); this.l1 = l1; this.l2 = l2; this.l3 = l3; this.fL.options.add(new Option("Select",-1));//给一级菜单添加一个"select"标志 for (var i = 0; i < l1.length; i++) { var item = new Option(l1[i], i); this.fL.options.add(item); } this.doLev2(); //调用doLev2函数，处理二级菜单 this.doLev3(); //调用doLev3函数，处理 * 菜单 }, removeSTL: function(){ //用于删除第二、 * 的菜单项 this.sL.options.length = 0; this.tL.options.length = 0; }, removeTL: function(){ //用于删除第 * 的菜单项 this.tL.options.length = 0; }, doLev2: function(){ //处理二级菜单 var that = this; this.fL.onchange = function(){ that.removeSTL(); //删除旧second的select if (that.fL.selectedIndex == 0) { that.removeSTL(); // //删除旧second的select } else { that.sL.options.add(new Option("Select", -1)); //给二级菜单添加一个"select"标志 //获取第二级所需的数组 var items = that.l2[that.fL.selectedIndex - 1]; for (var i = 0; i < items.length; i++) { //添加第二级的新select项 var item = new Option(items[i], i); that.sL.options.add(item); } } } }, doLev3: function(){ //处理 * 菜单 var that = this; this.sL.onchange = function(){ that.removeTL(); //删除旧third的select if (that.sL.selectedIndex == 0) { that.removeTL(); //删除旧third的select } else { that.tL.options.add(new Option("Select", -1)); //给 * 菜单添加一个"select"标志 //获取第 * 所需的数组 var items = that.l3[that.fL.selectedIndex - 1][that.sL.selectedIndex - 1]; for (var i = 0; i < items.length; i++) { //添加第 * 的新select项 var item = new Option(items[i], i); that.tL.options.add(item); } } } } } onload = function(){ Levels.init("first", "second", "third", level1,level2,level3); //调用Levels的init方法 } </script> </head> <body> <form> <select id="first"> </select> <select id="second"> </select> <select id="third"> </select> </form> </body> </html>

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javascript 三 级下拉选择菜单Levels对象

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