求解为什么有时候切换时会白屏.有没有更精简的方法..

预加载的preload  
var hrefs = document.querySelectorAll(".mui-bar-tab a");  
            for (var i = 0; i < hrefs.length; i++) {  
                if (hrefs[i].id == 'chatrooms_list_frame.html') {  
                    var chatroomsView = mui.preload({  
                        url: 'chatrooms_list_frame.html',  
                        id: 'chatrooms_list_frame.html',  
                        styles: {  
                            top: '45px',  
                            bottom: '50px',  
                        },  
                        extras: {  
                            mType: 'main'  
                        }  
                    });  
                } else {  
                    mui.preload({  
                        url: hrefs[i].id,  
                        id: hrefs[i].id,  
                        styles: {  
                            top: '45px',  
                            bottom: '50px',  
                        },  
                        extras: {  
                            mType: 'main'  
                        }  
                    })  
                }  
            }  
            var guideView = mui.preload({  
                url: 'guide.html',  
                id: 'guide.html',  
                styles: {  
                    top: '0px',  
                    bottom: '0px',  
                },  
                extras: {  
                    mType: 'main'  
                }  
            });  
            var signinView = mui.preload({  
                url: 'signin.html',  
                id: 'signin.html',  
                styles: {  
                    top: '0px',  
                    bottom: '0px',  
                },  
                extras: {  
                    mType: 'main'  
                }  
            });  
var switchTo = function(targetTab, targetTitle) {  
            if (targetTab == activeTab) {  
                return;  
            }  
            //切换到fullscreen pages  
            if (targetTab == 'guide.html' || targetTab == 'signin.html') {  
                plus.webview.getWebviewById(targetTab).show();  
                activeTab = targetTab;  
                //从me退出，去除active，防止再登录时显示chat&me双选项激活  
                document.getElementById('me.html').classList.remove("mui-active");  
                return;  
            }  
            //切换到tab pages，首先显示框架index页面   
            plus.webview.getLaunchWebview().show();  
            //显示目标选项卡  
            plus.webview.show(targetTab, 'slide-in-right', 200);  
            if (targetTab == 'chatrooms_list_frame.html') {  
                document.getElementById('chatrooms_list_frame.html').classList.add("mui-active");  
                title.innerHTML = targetTitle;  
                mvmsgWarn("chatnumb");  
            } else if (targetTab == 'transactions_list_frame.html') {  
                mvmsgWarn("transnumb");  
            }  
            //隐藏当前;  
            plus.webview.hide(activeTab);  
            //仅针对tab pages才更改标题和tab button样式  
            if (activeTab != 'guide.html' && activeTab != 'signin.html') {  
                //更新标题  
                title.innerHTML = targetTitle;  
                //取消当前所有的活跃样式  
                var classlist = document.body.querySelectorAll('.mui-bar-tab a')  
                for (var i = 0; i < classlist.length; i++) {  
                    classlist[i].classList.remove("mui-active");  
                }  
                //设置新的活跃样式  
                document.getElementById(targetTab).classList.add("mui-active");  
            }  
            //更改当前活跃的选项卡  
            activeTab = targetTab;  
        };