纯js 判断手势滑动方向

$('body').on('touchstart', '#gallerySlider img', function(e) {

var touch = e.originalEvent,

startX = touch.changedTouches[0].pageX;

startY = touch.changedTouches[0].pageY;

slider.on('touchmove', function(e) {

e.preventDefault();

touch = e.originalEvent.touches[0] ||

e.originalEvent.changedTouches[0];

if (touch.pageX - startX > 10) {

console.log("右划");

slider.off('touchmove');

showPrevious();

} else if (touch.pageX - startX < -10) {

console.log("左划");

slider.off('touchmove');

showNext();

};

if (touch.pageY - startY > 10) {

console.log("下划");

} else if (touch.pageY - startY < -10) {

console.log("上划");

};

});

        // Return false to prevent image
        // highlighting on Android
        return false;

    }).on('touchend', function() {
        slider.off('touchmove');
    });