picker控件在最下层怎么挪到上层

已解决。
子页面定义picker
隐藏控件绑定picker
父页面调用子页面方法。调用隐藏控件的tab事件。应该可以直接调用到父页面的picker的。
比较忙。懒得想了，上代码
子页面

    <input type="hidden" id="pickershow" />

    (function($, doc) {  
                $.init();  
                $.ready(function() {  
                    var userPicker = new $.PopPicker();  
                    userPicker.setData([{  
                        value: 'week',  
                        text: '一周'  
                    }, {  
                        value: 'halfmonth',  
                        text: '半个月'  
                    }, {  
                        value: 'onemonth',  
                        text: '一个月'  
                    }, {  
                        value: 'threemonth',  
                        text: '三个月'  
                    }]);  
                    var showUserPickerButton = doc.getElementById('pickershow');  
                    var userResult = doc.getElementById('stor_showUserPicker');  
                    showUserPickerButton.addEventListener('tap', function(event) {  
                        userPicker.show(function(items) {  
                            userResult.innerText = JSON.stringify(items[0].text).replace(/\"/g, "");;  
                        });  
                    }, false);  
                })  
            })(mui, document);  
            window.addEventListener('showpick', function() {  
                var showUserPickerButton = document.getElementById('pickershow');  
                mui.trigger(showUserPickerButton,'tap','');  
            });

父页面
var pickshow = function() {
var ordertwoPage = plus.webview.getWebviewById('ordertwo');
mui.fire(ordertwoPage, 'showpick');
}