这个方法已经试了，无法解决

    var overscroll = function(el) {
      el.addEventListener('touchstart', function() {
        var top = el.scrollTop
          , totalScroll = el.scrollHeight
        , currentScroll = top + el.offsetHeight
    //If we're at the top or the bottom of the containers
    //scroll, push up or down one pixel.
    //
    //this prevents the scroll from "passing through" to
    //the body.
        if(top === 0) {
          el.scrollTop = 1
        } else if(currentScroll === totalScroll) {
          el.scrollTop = top - 1
        }
    })
      el.addEventListener('touchmove', function(evt) {
        //if the content is actually scrollable, i.e. the content is long enough
        //that scrolling can occur
        if(el.offsetHeight < el.scrollHeight)
          evt._isScroller = true
    })
}
overscroll(document.querySelector('.outer'));
document.body.addEventListener('touchmove', function(evt) {
    //In this case, the default behavior is scrolling the body, which
    //would result in an overflow.  Since we don't want that, we preventDefault.
    if(!evt._isScroller) {
      evt.preventDefault()
    }
})