为什么不能使用js的原有方法获取指定id的对象

**mui('#list').on('tap', 'a', function() {

            var id = this.getAttribute('href');  
            var type = this.getAttribute("open-type");  
            if (type == "common") {  
                if (~id.indexOf('')) {  
                    var pop = ~id.indexOf('offcanvas-with-right') ? "close" : "none";  
                    mui.openWindow({  
                        id: id,  
                        url: this.href,  
                        styles: {  
                            zindex: 9999,  
                            popGesture: pop  
                        },  
                        waiting: {  
                            autoShow: false  
                        }  
                    });  
                } else {  
                    alert(222);  
                    mui.openWindow({  
                        id: id,  
                        url: this.href,  
                        waiting: {  
                            autoShow: false  
                        }  
                    });  
                }  
            } else {  
                                    //如何获取指定id的对象呢？  
                var moviename = this.getElementById("moviename");  
                alert("获取的id值"+moviename);  

                if (id && ~id.indexOf('.html')) {  
                    var href = this.href;  
                    //获得共用模板组  
                    var template = ~href.indexOf('pullrefresh.html')?getTemplate('pullrefresh'):getTemplate('default');  
                    //判断是否显示右上角menu图标；  
                    var showMenu = ~href.indexOf('popovers.html')?true:false;  
                    //获得共用父模板  
                    var headerWebview = template.header;  
                    //获得共用子webview  
                    var contentWebview = template.content;  
                    var title = this.innerText;  
                    //通知模板修改标题，并显示隐藏右上角图标；  
                    mui.fire(headerWebview,'updateHeader',{title:title,showMenu:showMenu});  
                    var reload = true;  
                    if (!template.loaded) {  
                        if (contentWebview.getURL() != this.href) {  
                            contentWebview.loadURL(this.href);  
                        } else {  
                            reload = false;  
                        }  
                    } else {  
                        reload = false;  
                    }  
                    (!reload) && contentWebview.show();  

                    headerWebview.show('slide-in-right', 150);  
                }  
            }  
        });  
        **  

应用HBuilder已启动...
Uncaught ReferenceError: mui is not defined
Uncaught ReferenceError: mui is not defined
Uncaught ReferenceError: mui is not defined
Uncaught TypeError: Object [object HTMLAnchorElement] has no method 'getElementById' at cinema.html:296
Uncaught TypeError: Object [object HTMLAnchorElement] has no method 'getElementById' at cinema.html:296