Layui 级联选择方法

1.先定义页面需要监听展现的元素 name="courseTemplate.levelId" class="state"

<div class="layui-input-inline">
	<select name="courseTemplate.levelId"  class="state">
		 <option value="">请选教育程度</option>
	</select>
</div>
<div class="layui-input-inline">
	<select name="courseTemplate.gradeId"  class="state" >
		<option value="">请选授课年级</option>
	</select>
</div>
<div class="layui-input-inline">
			<select name="courseTemplate.subjectId" class="state">
				<option value="">请选授课科目</option>
			</select>
</div>

2. javascipt 

layui.use(['layer', 'jquery', 'form'], function () {
    var layer = layui.layer,
        $ = layui.jquery,
        form = layui.form;
    var url = "${base}/course/courseTemplate/Com_JsonBaseEduGrade.do"; //数据请求地址
    var level = "";
    var grade = "";
    var subject = "";
    getJSON(url + "?treeType=1", $("select[name='courseTemplate.levelId']").closest("div")); //初始化第一个元素
    var type;

    form.on('select(state)', function (data) { //进行监听 看元素是否变化，获取下一个下拉框数据
        $that = $(data.elem);
        type = data.elem.name;
        var urls = "";
        if (type == "courseTemplate.levelId") {
            urls = url + "?treeType=2&levelId=" + data.value;
        } else
        if (type == "courseTemplate.gradeId") {
            var levelId = $("select[name='courseTemplate.levelId']").val();
            urls = url + "?treeType=3&levelId=" + levelId + "&gradeId=" + data.value;
        }
        getJSON(urls, $that.closest("div").next());
    });


    function getJSON(urls, even) {
        $.getJSON(urls, function (json) {
            var pid = 0;
            var name = even.find("select").attr("name");
            var select = "<select name=\"" + name + "\" lay-filter=\"state\">";
            select += "<option value=\"0\">请选择 </option>";

            $(json).each(function () {
                select += "<option value=\"" + this.id + "\"";
                if (level == this.nameCn || grade == this.nameCn || subject == this.nameCn) {
                    select += " selected=\"selected\" ";
                    pid = this.id;
                }
                select += ">" + this.nameCn + "</option>";
            });
            select += "</select>";
            even.html(select);

            var nextName = even.next().find("select").attr("name");
            even.next().html("<select name=\"" + nextName + "\" lay-filter=\"state\"><option value=\"0\">请选择 </option></select>");
            form.render('select');
            if (pid != 0) {
                var urls = "";
                if (name == "courseTemplate.levelId") {
                    urls = url + "?treeType=2&levelId=" + pid;
                } else if (name == "courseTemplate.gradeId") {
                    var levelId = $("select[name='courseTemplate.levelId']").val();
                    urls = url + "?treeType=3&levelId=" + levelId + "&gradeId=" + pid;
                }
                getJSON(urls, even.next());
            }
        });
    }
});