layui中select下拉菜单的监听

<div class="layui-input-inline" style="width: 100%!important;">
        <label for="" class="layui-form-label" style="width: 90px!important;">选择尺寸：</label>
        <div class="layui-inline">
                <select id="codeSize" lay-filter="codeSize">
                        <option value="80">80mm * 80mm</option>
                        <option value="20">20mm * 20mm</option>
                        <option value="160">160mm * 160mm</option>
                        <option value="420" selected>420mm * 420mm</option>
                        <option value="250">250mm * 250mm</option>
                </select>
        </div>
</div>

//监听尺寸
form.on('select(codeSize)', function (data) {
        var load = layer.load(1);
        switch (data.value) {
                case "420":
                        widthHeight = new unitConversion().mmConversionPx(420);
                        break;
                case "250":
                        widthHeight = new unitConversion().mmConversionPx(250);
                        break;
                case "160":
                        widthHeight = new unitConversion().mmConversionPx(160);
                        break;
                case "80":
                        widthHeight = new unitConversion().mmConversionPx(80);
                        break;
                case "20":
                        widthHeight = new unitConversion().mmConversionPx(20);
                        break;
        }
        loadCode(widthHeight, correctLevel, layer, load);
});