1.html

<select id="itemName">
<!--下拉框数据动态加载-->
</select>

2.js:(使用jquery)

$(document).ready(function () { //此处页面打开即请求api
                $.ajax({
                    type:'GET',
                    url:"请求地址",
                    contentType: "application/json; charset=utf-8",
                    async : true ,
                    dataType: "json",
                    success: function (date) {
                        var optionstring = "";
                        for (var j = 0; j < date.length;j++) {
                            optionstring += "<option value='" + date[j].id + "'>" +date[j].name+" " + "</option>";
                            $("#select").html("<option value='0'>请选择...</option> "+optionstring);
                        }
                    },
                    error: function (msg) {
                        layer.msg('数据出错了!!');
                    }
                });
            });

3.layui 注意

layui需在请求成功后重新渲染，增加以下代码

 form.render('select');