根据参数显示类别（三级联动，需要JSON数据）

根据参数显示类别（三级联动，需要JSON数据）

Scripts/Category.js

调用方法：

$(function () {

BindCategory();

//默认绑定文本框中的值

BindCategoryData($("#txtCategoryId").val());

})

绑定三级联动（详情见：http://www.cnblogs.com/haozhenjie819/p/3887279.html）

function BindCategory() {

var $txtCategory = $("#txtCategoryId");

var _selectId = ["selBigClass", "selSmallClass", "selThreeClass"];

for (var i = 0; i < _selectId.length; i++) {

var select = document.createElement("select");

select.id = _selectId[i];

select.name = _selectId[i];

$txtCategory.parent().append(select);

}

var $selBigClass = $("#selBigClass");

var $selSmallClass = $("#selSmallClass");

var $selThreeClass = $("#selThreeClass");

$selSmallClass.hide();

$selThreeClass.hide();

$.getJSON("/Scripts/CategoryJson.js", function (json) {

var html = ['<option value="">请选择大类</option>'];

for (var key in json) {

if (json[key].pid == 0) {

html.push('<option value="' + json[key].id + '">' + json[key].name + '</option>');

}

}

//第一级类别

$selBigClass.empty().append(html.join('')).change(function () {

$txtCategory.val(this.value);

$selThreeClass.hide();

$selSmallClass.show();

var html = ['<option value="">请选择小类</option>'];

for (var data in json) {

if (json[data].pid == $("#selBigClass").val()) {

html.push('<option value="' + json[data].id + '">' + json[data].name + '</option>');

}

}

//第二级类别

$selSmallClass.empty().append(html.join('')).change(function () {

$txtCategory.val(this.value);

$selThreeClass.show();

var html = ['<option value="">请选择小类</option>'];

for (var data in json) {

if (json[data].pid == $selSmallClass.val()) {

html.push('<option value="' + json[data].id + '">' + json[data].name + '</option>');

}

}

//第三级类别

$selThreeClass.empty().append(html.join('')).change(function () {

$txtCategory.val(this.value);

});

//如果不存在第三级类别则隐藏第三级类别控件

if ($selThreeClass.get(0).options.length <= 1) {

$selThreeClass.hide();

return false;

}

});

//如果不存在第二级类别则隐藏第二级类别控件

if ($selSmallClass.get(0).options.length <= 1) {

$selSmallClass.hide();

return false;

}

});

});

};

根据参数显示默认值

var setBigClassTime;

//绑定数据

function BindCategoryData(CategoryId) {

if (document.getElementById("selBigClass") == null || document.getElementById("selBigClass").length <= 0)

setBigClassTime = setTimeout("BindCategoryData('" + CategoryId + "')", 200);

else

clearTimeout(setBigClassTime);

$.getJSON('/Scripts/CategoryJson.js', function (json) {

for (var key in json) {

if (json[key].id == CategoryId) {

json[key].id = CategoryId;

var str = json[key].itemvalue;

var _p = str.split("|")[2];

var _c = json[key].pid;

if (_p == _c) {

if (_p != "") {

$("#selBigClass").val(_p).change();

$("#selSmallClass").val(CategoryId);

}

else {

$("#selBigClass").val(CategoryId);

}

}

else {

$("#selBigClass").val(_p).change();

$("#selSmallClass").val(_c).change();

$("#selThreeClass").val(CategoryId).change();

}

}

}

});

}

Scripts/CategoryJson.js（如何生成json数据详见：http://www.cnblogs.com/haozhenjie819/p/3601676.html）

[{ "id": 31, "name": "\u65b0\u95fb\u4e2d\u5fc3", "pid": 0, "itemvalue": "|0|" },

{ "id": 59, "name": "\u52a0\u76df\u5408\u4f5c", "pid": 0, "itemvalue": "|0|" },

{ "id": 65, "name": "\u4ea7\u54c1\u670d\u52a1", "pid": 0, "itemvalue": "|0|" },

{ "id": 60, "name": "\u52a0\u76df\u987b\u77e5", "pid": 59, "itemvalue": "|0|59|" },

{ "id": 61, "name": "\u52a0\u76df\u6d41\u7a0b", "pid": 59, "itemvalue": "|0|59|" },

{ "id": 62, "name": "\u52a0\u76df\u533a\u57df", "pid": 59, "itemvalue": "|0|59|" },

{ "id": 70, "name": "\u63a8\u8350\u670d\u52a1", "pid": 65, "itemvalue": "|0|65|" },

{ "id": 71, "name": "\u8ba1\u8d39\u65b9\u5f0f", "pid": 65, "itemvalue": "|0|65|" },

{ "id": 72, "name": "\u7528\u6237\u987b\u77e5", "pid": 65, "itemvalue": "|0|65|" },

{ "id": 73, "name": "\u7981\u5bc4\u8303\u56f4", "pid": 65, "itemvalue": "|0|65|" },

{ "id": 75, "name": "\u666e\u901a\u5feb\u9012", "pid": 70, "itemvalue": "|0|65|70|" },

{ "id": 76, "name": "\u7279\u79cd\u5feb\u4ef6", "pid": 70, "itemvalue": "|0|65|70|" },

{ "id": 77, "name": "\u9650\u65f6\u6d3e\u9001", "pid": 70, "itemvalue": "|0|65|70|" },

{ "id": 78, "name": "\u4ee3\u6536\u8d37\u6b3e", "pid": 70, "itemvalue": "|0|65|70|" },

{ "id": 79, "name": "\u4fdd\u4ef7\u670d\u52a1", "pid": 70, "itemvalue": "|0|65|70|" },

{ "id": 80, "name": "\u4ee3\u7b7e\u56de\u5355", "pid": 70, "itemvalue": "|0|65|70|"}]

web页面（给hidden赋值，类别编号为75）

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

<title>三级联动</title>

<script src="/Scripts/jquery-1.4.1.min.js" type="text/javascript"></script>

<script src="/Scripts/Category.js" type="text/javascript"></script>

</head>

<body>

<form id="form1" runat="server">

<table>

<tr>

<td >新闻类别：</td>

<td > <input id="txtCategoryId" name="txtCategoryId" type="hidden" runat="server" value="75" /></td>

</tr>

</table>

</form>

</body>

</html>

效果图

涉及的知识点：【JavaScript split() 方法】返回值是一个字符串数组。