滑动检测

Question

我使用以下代码进行滑动检测。它工作正常。

    function swipedetect(el, callback){

 var touchsurface = el,
 swipedir,
 startX,
 startY,
 distX,
 distY,
 threshold = 150, //required min distance traveled to be considered swipe
 restraint = 100, // maximum distance allowed at the same time in perpendicular direction
 allowedTime = 300, // maximum time allowed to travel that distance
 elapsedTime,
 startTime,
 handleswipe = callback || function(swipedir){}

 touchsurface.addEventListener('touchstart', function(e){
  var touchobj = e.changedTouches[0]
  swipedir = 'none'
  dist = 0
  startX = touchobj.pageX
  startY = touchobj.pageY
  startTime = new Date().getTime() // record time when finger first makes contact with surface
  e.preventDefault()

 }, false)

 touchsurface.addEventListener('touchmove', function(e){
  e.preventDefault() // prevent scrolling when inside DIV
 }, false)

 touchsurface.addEventListener('touchend', function(e){
  var touchobj = e.changedTouches[0]
  distX = touchobj.pageX - startX // get horizontal dist traveled by finger while in contact with surface
  distY = touchobj.pageY - startY // get vertical dist traveled by finger while in contact with surface
  elapsedTime = new Date().getTime() - startTime // get time elapsed
  if (elapsedTime <= allowedTime){ // first condition for awipe met
   if (Math.abs(distX) >= threshold && Math.abs(distY) <= restraint){ // 2nd condition for horizontal swipe met
    swipedir = (distX < 0)? 'left' : 'right' // if dist traveled is negative, it indicates left swipe
   }
   else if (Math.abs(distY) >= threshold && Math.abs(distX) <= restraint){ // 2nd condition for vertical swipe met
    swipedir = (distY < 0)? 'up' : 'down' // if dist traveled is negative, it indicates up swipe
   }
  }
  handleswipe(swipedir)
  e.preventDefault()
 }, false)
}

它工作正常但是对于少数页面我有滚动（本机），这是无效的。我尝试从触摸事件中删除e.preventDefault()，然后滚动工作正常，但不能滑动。我如何确保两者都有效？