jquery实现相册一下滑动两次的方法

var t1=null; //定义为全局变量$('body').on('touchstart', '#gallerySlider img', function(e){var touch = e.originalEvent,startX = touch.changedTouches[0].pageX;if (t1 == null){    t1 = new Date().getTime();}else{        var t2 = new Date().getTime();    if(t2 - t1 < 500){      t1 = t2;      return;    }else{      t1 = t2;    }}slider.on('touchmove',function(e){event.stopPropagation();touch = e.originalEvent.touches[0] ||e.originalEvent.changedTouches[0];if(touch.pageX - startX > 10){slider.off('touchmove');showPrevious();}else if (touch.pageX - startX < -10){slider.off('touchmove');showNext();}});return false;}).on('touchend',function(){slider.off('touchmove');});