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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(
'.scroll'
));
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();
}
});
正文完