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How to disable rubber band in iOS web apps?

This:

$('body').on('touchmove', function(e) { e.preventDefault(); }); 

Works, but will disable scrolling throughout the whole page, which is far from ideal.

This:

$('*').on('touchstart', function(e){     var element = $(this).get(0);      if ( element.scrollTop <= 0 )                                           element.scrollTop = 1;     if ( element.scrollTop + element.offsetHeight >= element.scrollHeight ) element.scrollTop = element.scrollHeight - element.offsetHeight - 1; }); 

Works on pages that have a scrolling area. However when there is nothing to scroll it will again show the rubber-band.

So my question:

How can you disable the rubber band effect and still keep the -webkit-overflow-scrolling areas scrollable?

[Update]

Best Solution

Disable scrolling on all non-scrollable elements such as a tab bar or a navigation bar.

anElement.addEventListener('touchmove', function( event ){ event.preventDefault() }; 

Attach a scroll handler to the scrollable elements such as the main content.

anElement.addEventListener('touchstart', function( event ){         if( this.scrollTop === 0 ) {             this.scrollTop += 1;         } else if( this.scrollTop + this.offsetHeight >= this.scrollHeight ) {             this.scrollTop -= 1;         } } 
like image 382
Mark Avatar asked Apr 27 '12 21:04

Mark


2 Answers

Ran into the same issue recently with a SPA where the <body> rubber-banding was detracting from the experience, but I needed scrolling in sub-areas. Many thanks to dSquared's suggestions, as Method 1 worked best for me. Here is my small expansion of his suggestion that I implemented in a project for work that looks all the way up the tree to find any elements (not just divs) that have a .scroll class on it:

// Prevent rubber-banding of the body, but allow for scrolling elements $('body').on('touchmove', function (e) {     var searchTerms = '.scroll, .scroll-y, .scroll-x',         $target = $(e.target),         parents = $target.parents(searchTerms);      if (parents.length || $target.hasClass(searchTerms)) {         // ignore as we want the scroll to happen         // (This is where we may need to check if at limit)     } else {         e.preventDefault();     } }); 

And here is what the CSS looks like:

body {     height: 100%;     overflow: hidden; } .scroll, .scroll-y, .scroll-x {     -webkit-overflow-scrolling: touch; } .scroll > *, .scroll-y > *, .scroll-x > * {     -webkit-transform : translateZ(0); } .scroll { overflow: auto; } .scroll-y { overflow-y: auto; } .scroll-x { overflow-x: auto; } 

You only need one library (jQuery or Zepto) and you get native scrolling with momentum and no rubber-banding on the body. Also, I've added the translateZ to fix some issues I've had with elements disappearing during scrolling and it can be used to GPU accelerate your elements.

BUT (and this is a big but), as dSquared points out, the whole page rubber-bands when the scroll element is at its limit and attempted to scroll further. Personally, I consider this a failure so I'm continuing to work on it, just wanted to pitch in on trying to figure this out. Adding a check along the lines of the OP's code might be the answer, but I haven't tried it.

UPDATE (10/7/12):

After lots of work, I've gotten the following code working perfectly in iOS6 (haven't tested in anything else). No rubber-banding on the body, no more issues when at the limit of the scroll area, and it has native scrolling performance throughout. It's obviously a lot more code that originally, but I think this will give the behavior closest to the OP's goals.

(function registerScrolling($) {     var prevTouchPosition = {},         scrollYClass = 'scroll-y',         scrollXClass = 'scroll-x',         searchTerms = '.' + scrollYClass + ', .' + scrollXClass;      $('body').on('touchstart', function (e) {         var $scroll = $(e.target).closest(searchTerms),             targetTouch = e.originalEvent.targetTouches[0];          // Store previous touch position if within a scroll element         prevTouchPosition = $scroll.length ? { x: targetTouch.pageX, y: targetTouch.pageY } : {};     });  $('body').on('touchmove', function (e) {     var $scroll = $(e.target).closest(searchTerms),         targetTouch = e.originalEvent.targetTouches[0];      if (prevTouchPosition && $scroll.length) {         // Set move helper and update previous touch position         var move = {             x: targetTouch.pageX - prevTouchPosition.x,             y: targetTouch.pageY - prevTouchPosition.y         };         prevTouchPosition = { x: targetTouch.pageX, y: targetTouch.pageY };          // Check for scroll-y or scroll-x classes         if ($scroll.hasClass(scrollYClass)) {             var scrollHeight = $scroll[0].scrollHeight,                 outerHeight = $scroll.outerHeight(),                  atUpperLimit = ($scroll.scrollTop() === 0),                 atLowerLimit = (scrollHeight - $scroll.scrollTop() === outerHeight);              if (scrollHeight > outerHeight) {                 // If at either limit move 1px away to allow normal scroll behavior on future moves,                 // but stop propagation on this move to remove limit behavior bubbling up to body                 if (move.y > 0 && atUpperLimit) {                     $scroll.scrollTop(1);                     e.stopPropagation();                 } else if (move.y < 0 && atLowerLimit) {                     $scroll.scrollTop($scroll.scrollTop() - 1);                     e.stopPropagation();                 }                  // If only moving right or left, prevent bad scroll.                 if(Math.abs(move.x) > 0 && Math.abs(move.y) < 3){                   e.preventDefault()                 }                  // Normal scrolling behavior passes through             } else {                 // No scrolling / adjustment when there is nothing to scroll                 e.preventDefault();             }         } else if ($scroll.hasClass(scrollXClass)) {             var scrollWidth = $scroll[0].scrollWidth,                 outerWidth = $scroll.outerWidth(),                  atLeftLimit = $scroll.scrollLeft() === 0,                 atRightLimit = scrollWidth - $scroll.scrollLeft() === outerWidth;              if (scrollWidth > outerWidth) {                 if (move.x > 0 && atLeftLimit) {                     $scroll.scrollLeft(1);                     e.stopPropagation();                 } else if (move.x < 0 && atRightLimit) {                     $scroll.scrollLeft($scroll.scrollLeft() - 1);                     e.stopPropagation();                 }                 // If only moving up or down, prevent bad scroll.                 if(Math.abs(move.y) > 0 && Math.abs(move.x) < 3){                   e.preventDefault();                 }                  // Normal scrolling behavior passes through             } else {                 // No scrolling / adjustment when there is nothing to scroll                 e.preventDefault();             }         }     } else {         // Prevent scrolling on non-scrolling elements         e.preventDefault();     } }); })(jQuery); 
like image 131
Tim Hall Avatar answered Sep 20 '22 11:09

Tim Hall


Unfortunately there isn't a 'magic bullet' fix for this as the rubber-band scrolling on Mobile Safari is an inbuilt 'feature' of the browser itself. By using any default scrolling mechanism provided by the browser, you will end up with the rubber-band scrolling to some degree.

There are two ways I would suggest to tackle this:

Method 1

Bind to the touchmove event on the </body> element and check the target of the touchmove event to see if you want it to fire or not like so:

HTML

<div class="scroll">     <p>...</p>     <p>...</p> </div> 

JS

$('body').on('touchmove', function(e) {     // this is the node the touchmove event fired on     // in this example it would be the </p> element     target = e.target;      // we need to find the parent container     // we get it like so; assumes div as parent     parent = $(e.target).closest('div');      // check if the parent is a scroll window by class //     if ($(parent).hasClass('scroll')){         // ignore as we want the scroll to happen     } else {         e.preventDefault();     } }); 

JSFiddle Example Here

This method uses the default scrolling of the browser, however it has the drawback that you will still have the rubber-band scrolling when at the top or bottom of the scroll </div>.

Method 2

Bind to the touchmove event of the </body> element as before, however in this case we prevent All touchmove events and rely on the excellent iScroll 4 plugin to handle the scrolling, like so:

HTML

<div id="wrapper">     <div id="scroller">         <p>...</p>         <p>...</p>     </div> </div> 

JS

$(document).ready(function(){     // prevent all scroll //     $('body').on('touchmove', function(e) {         e.preventDefault();     });      // apply iscroll to scrolling element     // requires use of id     var newscroll = new iScroll('wrapper'); });​​ 

JSFiddle Example Here

This is my preferred method as it blocks all rubber-band scrolling and provides a nice scrolling area, however it relies on the use of a plugin.

I hope this helps

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dSquared Avatar answered Sep 18 '22 11:09

dSquared