Scripts/Category.js
//Jquery三级类别联动
$(function () {
BindCategory();
})
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;
} });
});
};
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|"}]
html页面
<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" /></td>
</tr>
</table>
</form>
</body>
</html>
效果图
知识点：1、Jquery获取select中option个数
$("#selSmallClass").get(0).options.length