layui.form.render();
<div class="layui-form-item">
<label class="layui-form-label">选择框</label>
<div class="layui-input-block">
<select name="city" lay-verify="required">
<option value=""></option>
<option value="0">北京</option>
<option value="1">上海</option>
<option value="2">广州</option>
<option value="3">深圳</option>
<option value="4">杭州</option>
</select>
</div>
</div>