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Under Mobile Safari, is it possible to allow one absolutely positioned div to scroll without allowing the entire page to bob up and down when it the scroll reaches the edges (elastically scrolling)?
Here is a minimal working example of the issue I'm facing:
<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no">
<meta name="apple-mobile-web-app-capable" content="yes" />
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
#a, #b {
position: absolute;
top: 0;
left: 0;
height: 100%;
padding: 10px;
overflow: auto;
}
#a {
width: 80px;
background: #f00;
}
#b {
background: #00f;
left: 80px;
width: 100%;
}
</style>
<script src="http://code.jquery.com/jquery-1.10.1.min.js"></script>
<script>
function pdcb(e) {
e.preventDefault();
}
function npcb(e) {
e.stopPropagation();
}
$(document).on('touchstart touchmove', pdcb).
on('touchstart touchmove', '.scrollable', npcb);
</script>
</head>
<body>
<div id="a" class="scrollable">
This<br>
should<br>
be<br>
scrollable<br>
but<br>
not<br>
scroll<br>
the<br>
whole<br>
page<br>
This<br>
should<br>
be<br>
scrollable<br>
but<br>
not<br>
scroll<br>
the<br>
whole<br>
page<br>
This<br>
should<br>
be<br>
scrollable<br>
but<br>
not<br>
scroll<br>
the<br>
whole<br>
page<br>
This<br>
should<br>
be<br>
scrollable<br>
but<br>
not<br>
scroll<br>
the<br>
whole<br>
page<br>
This<br>
should<br>
be<br>
scrollable<br>
but<br>
not<br>
scroll<br>
the<br>
whole<br>
page<br>
</div>
<div id="b">
this should never scroll
</div>
</body>
</html>
Solution:
$(document).on('touchmove', function(e) {
e.preventDefault();
}).ready(function() {
$(".scrollable").on('touchstart', function(e) {
this.allowUp = (this.scrollTop > 0);
this.allowDown = (this.scrollTop < this.scrollHeight - this.clientHeight);
this.prevTop = null;
this.prevBot = null;
this.lastY = e.originalEvent.pageY;
}).on('touchmove', function(e) {
var event = e.originalEvent;
var up = (event.pageY > this.lastY), down = !up;
this.lastY = event.pageY;
if ((up && this.allowUp) || (down && this.allowDown))
event.stopPropagation();
else
event.preventDefault();
});
});
234
The original answers are fantastic, but have a few flaws that I resolved:
My answer addresses those. (Notice that I use .scroll-y, instead of .scrollable)
First, add these CSS rules:
.scroll-y {
overflow-y: auto;
overflow-x: hidden;
-webkit-overflow-scrolling: touch; /* nice webkit native scroll */
}
Add the .scroll-y class to any elements you want to make scroll.
Then, add this JS somewhere:
// Disable scroll for the document, we'll handle it ourselves
$(document).on('touchmove', function(e) {
e.preventDefault();
});
// Check if we should allow scrolling up or down
$(document.body).on("touchstart", ".scroll-y", function (e) {
// If the element is scrollable (content overflows), then...
if (this.scrollHeight !== this.clientHeight) {
// If we're at the top, scroll down one pixel to allow scrolling up
if (this.scrollTop === 0) {
this.scrollTop = 1;
}
// If we're at the bottom, scroll up one pixel to allow scrolling down
if (this.scrollTop === this.scrollHeight - this.clientHeight) {
this.scrollTop = this.scrollHeight - this.clientHeight - 1;
}
}
// Check if we can scroll
this.allowUp = this.scrollTop > 0;
this.allowDown = this.scrollTop < (this.scrollHeight - this.clientHeight);
this.lastY = e.originalEvent.pageY;
});
$(document.body).on('touchmove', ".scroll-y", function(e) {
var event = e.originalEvent;
var up = event.pageY > this.lastY;
var down = !up;
this.lastY = event.pageY;
if ((up && this.allowUp) || (down && this.allowDown)) {
event.stopPropagation();
} else {
event.preventDefault();
}
});
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