JS 禁止安卓端返回键

            XBack = {};
            (function(XBack) {
                XBack.STATE = 'x - back';
                XBack.element;
                XBack.onPopState = function(event) {
                    event.state === XBack.STATE && XBack.fire();
                    XBack.record(XBack.STATE); //初始化事件时，push一下  
                };
                XBack.record = function(state) {
                    history.pushState(state, null, location.href);
                };
                XBack.fire = function() {
                    var event = document.createEvent('Events');
                    event.initEvent(XBack.STATE, false, false);
                    XBack.element.dispatchEvent(event);
                };
                XBack.listen = function(listener) {
                    XBack.element.addEventListener(XBack.STATE, listener, false);
                };
                XBack.init = function() {
                    XBack.element = document.createElement('span');
                    window.addEventListener('popstate', XBack.onPopState);
                    XBack.record(XBack.STATE);
                };
            })(XBack); // 引入这段js文件  
            XBack.init();
            XBack.listen(function() {});