h5 左右滑动切换tab栏

            on: {
                touchstart(e){
                    e.preventDefault();
                    var touch = e.touches[0];
                    startX = touch.pageX;
                    startT = new Date().getTime(); //记录手指按下的开始时间
                    // isMove = false; //是否产生滑动
                },
                touchmove(e){
                    // console.log('touchmove', e);
                    e.preventDefault();
                    var touch = e.touches[0];
                    var deltaX = touch.pageX - startX;
                },
                touchend(e){
                    // console.log(e)
                    var touch = e.changedTouches[0]
                    var endX = touch.pageX
                    
                    var index = me.list.indexOf(me.value)


                    var deltaT = new Date().getTime() - startT;
                    
                    var deltaX = touch.pageX - startX;
                    if (deltaT < 300){
                        if (deltaX > 0){
                            console.log('index', index);
                            
                            if (index === 0) {
                                index = me.list.length
                            }
                            me.$emit("input", me.list[--index])
                        } else if (deltaX < 0) {

                            if (index === me.list.length - 1) {
                                index = -1
                            }
                            me.$emit("input", me.list[++index])
                            console.log('index', index);
                            
                        }
                    } else {

                        if (deltaX > bodyWidth * 0.5){
                            console.log('index', index);
                            
                            if (index === 0) {
                                index = me.list.length
                            }
                            me.$emit("input", me.list[--index])
                        } else if (deltaX < -bodyWidth * 0.5) {

                            if (index === me.list.length - 1) {
                                index = -1
                            }
                            me.$emit("input", me.list[++index])
                            console.log('index', index);
                            
                        }
                    }
                    
                        
                    me._getActiveNav()
                }
            }