根据参数显示类别（三级联动，需要JSON数据）

$(function () {
    BindCategory();
    //默认绑定文本框中的值
    BindCategoryData($("#txtCategoryId").val());
})

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;
            }
           
        });
    });
};

[{ "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|"}]