``` var h = document.documentElement.clientHeight, mybody = document.getElementsByTagName('body')[0]; mybody.style.height = h + 'px'; //返回角度 function GetSlideAngle(dx,dy) { return Math.atan2(dy,dx) * 180 / Math.PI; } //根據起點和終點返回方向 1：向上，2：向下，3：向左，4：向右,0：未滑動 function GetSlideDirection(startX,startY, endX, endY) { var dy = startY - endY; var dx = endX - startX; var result = 0; //如果滑動距離太短 if (Math.abs(dx) < 2 && Math.abs(dy) < 2) { return result; } var angle = GetSlideAngle(dx, dy); if (angle >= -45 && angle < 45) { result = 4; }else if (angle >= 45 && angle < 135) { result = 1; }else if (angle >= -135 && angle < -45) { result = 2; }else if ((angle >= 135 && angle <= 180) || (angle >= -180 && angle < -135)) { result = 3; } return result; } //滑動處理 var startX, startY; mybody.addEventListener('touchstart', function (ev){ ev.preventDefault(); startX = ev.touches[0].pageX; startY = ev.touches[0].pageY; }, false); mybody.addEventListener('touchmove', function (ev){ var endX, endY; ev.preventDefault(); endX = ev.changedTouches[0].pageX; endY = ev.changedTouches[0].pageY; var direction = GetSlideDirection(startX, startY, endX, endY); switch (direction){ case 0: alert("沒滑動"); break; case 1: alert("向上"); break; case 2: alert("向下"); break; case 3: alert("向左"); break; case 4: alert("向右"); break; default: } }, false); ```