I have a sidebar on my site that occasionally needs to be scrolled. It's an unpleasant user experience when, after scrolling the sidebar to the bottom with the mousewheel, the main window begins to scroll.
I'd like to make sure the main window does not scroll with the mouse wheel when the mouse wheel is over my sidebar, though preferably only when my sidebar itself is showing scrollbars.
I'd probably like to avoid use of javascript scroll bars as they seem to often not perform as well as the defaults (laggier, wait on other js code, etc), though it looks like this solution may require them.
Thanks!
EDIT::
Here's the code I ended up using, a simple adaptation of what I found in the first link from my accepted answer.
(function($) {
$.fn.hasScrollBar = function() {
return this.get(0).scrollHeight > this.height();
}
})(jQuery);
/** This is high-level function.
* It must react to delta being more/less than zero.
*/
function handle(delta) {
slider = $('#wl-slider');
if(slider.hasScrollBar()){
if (delta > 0 && slider.scrollTop() == 0 && slider.hasClass('scroll-hover')){
event.preventDefault();
event.returnValue = false;
}
else if (delta < 0 && (slider.get(0).scrollHeight - slider.scrollTop() == slider.outerHeight()) && slider.hasClass('scroll-hover')){
event.preventDefault();
event.returnValue = false;
}
}
}
/** Event handler for mouse wheel event.
*/
function wheel(event){
var delta = 0;
if (!event) /* For IE. */
event = window.event;
if (event.wheelDelta) { /* IE/Opera. */
delta = event.wheelDelta/120;
} else if (event.detail) { /** Mozilla case. */
/** In Mozilla, sign of delta is different than in IE.
* Also, delta is multiple of 3.
*/
delta = -event.detail/3;
}
/** If delta is nonzero, handle it.
* Basically, delta is now positive if wheel was scrolled up,
* and negative, if wheel was scrolled down.
*/
if (delta)
handle(delta);
}
/** Initialization code.
* If you use your own event management code, change it as required.
*/
if($('#user-level').size() != 0)
{
if (window.addEventListener)
/** DOMMouseScroll is for mozilla. */
window.addEventListener('DOMMouseScroll', wheel, false);
/** IE/Opera. */
window.onmousewheel = document.onmousewheel = wheel;
}
I guess you won't suffice with standard event handlers e.g. in jquery and you need to handle directly the mouse wheel - I just googled these resources:
http://www.adomas.org/javascript-mouse-wheel/
http://www.javascriptkit.com/javatutors/onmousewheel.shtml
And then look directly if the sidebar is already scrolled at the bottom/top and if yes, filter out the scroll event.
Related
I wrote this code to add swipe function for an image slider. The slider is working correctly.
However when i perform a right or left swipe there is some vertical scrolling which is distracting and annoying.
I'm storing the reference to touchstart in the touch object.
And on touchend event, if vertical distance (lenY) is more than 50, i trigger preventDefault on the touchstart.
This isn't working.
Simplest option is to call preventDefault directly on touchStart. But the image slider occupies a large part of the mobile screen making scrolling down the page tricky.
I need to pass the lenY (vertical distance) to the touch start handler to prevent default action.
function triggerTouch() {
"use strict";
var tZone = document.getElementById('sl-m'),
touch = {},
startX = 0,
startY = 0,
endX = 0,
endY = 0;
if (tZone) {
tZone.addEventListener('touchstart', function (e) {
startX = e.changedTouches[0].screenX;
startY = e.changedTouches[0].screenY;
// store reference to touch event
touch.start = e;
}, false);
tZone.addEventListener('touchend', function (e) {
endX = e.changedTouches[0].screenX;
endY = e.changedTouches[0].screenY;
var lenX = Math.abs(endX - startX);
var lenY = Math.abs(endY - startY);
// check if user intended to scroll down
if (lenY < 50 && lenX > 50) {
touch.start.preventDefault();
e.preventDefault();
swipe(tZone, startX, endX);
}
}, false);
}
}
Since i haven't got an answer i am posting my own answer, hoping someone can provide the correct implementation.
I ended up using the css overflow property to temporarily disable vertical scroll.
This works perfectly though there is a small side effect. Once you swipe through the image slider, the scroll is disabled.
A swipe upwards is required to restore scroll to the page. Its not noticeable but i still want to figure the right way.
var touch = {};
window.onload = function () {
"use strict";
document.body.addEventListener("touchstart", touchHandler);
document.body.addEventListener("touchend", touchHandler);
};
function touchHandler(e) {
"use strict";
var el = e.target;
if (el.parentNode.id === "sl-m") {
if (e.type === "touchstart") {
touch.startX = e.changedTouches[0].screenX;
touch.startY = e.changedTouches[0].screenY;
} else {
touch.endX = e.changedTouches[0].screenX;
touch.endY = e.changedTouches[0].screenY;
touch.lenX = Math.abs(touch.endX - touch.startX);
touch.lenY = Math.abs(touch.endY - touch.startY);
if (touch.lenY < 20) {
// disable scroll
document.body.style.overflowY = "hidden";
// do swipe related stuff
swipe(el.parentNode);
} else {
// enable scroll if swipe was not intended
document.body.style.overflowY = "scroll";
}
}
} else {
// keep scroll enabled if touch is outside the image slider
document.body.style.overflowY = "scroll";
}
}
I want to share the solution that works for me. The above solution did not work on ios. I am sorry for my English. I do not know english.
function stop(e){
e=e || event;
e.preventDefault;
}
window.onscroll=stop(); //-->Yes, we will use it ..
For example, where you will use;
function move(event){
var finish=event.touches[0].clientX;
var verticalFinish=event.touches[0].clientY;
var diff=finish-strt;
var verticalDiff=verticalStrt-verticalFinish;
var f;
if(diff<0 && (Math.abs(diff)>Math.abs(verticalDiff)/3)){
f=verticalDiff+widthOffset;
slayt[x].style.left=diff+"px";
slayt[x].style.transition="none";
slayt[y].style.left=f+"px";
slayt[y].style.transition="none";
window.onscroll=stop(); //-->we used it here :)
}
else if(diff>0 && (Math.abs(diff)>Math.abs(verticalDiff)/3)){
f=diff-widthOffset;
slayt[x].style.left=diff+"px";
slayt[x].style.transition="none";
slayt[z].style.left=f+"px";
slayt[z].style.transition="none";
window.onscroll=stop();//-->we used it here :)
}
}
but there is a small problem. cancels if there is another function related to scrolling. return true; it does not work. I also write twice if I have a function related to the slider inside and outside the touchend.
function end(event){
//"touchend" related codes...
//bla bla
window.onscroll=function(){m=window.pageYOffset;console.log(m);if(m>=850)
{buton.style.display="block";}else{buton.style.display="none";}}
}
If it is useful, I will be happy...
Update :
I typed wrong. I want to fix. Actually, the scroll event cannot be canceled unfortunately. So the event we canceled above, scroll is not a vertical scroll event. All events.
window.onscroll=stop(); // ==>improper use
stop(); // ==> actually - Correct usage
It just needs to be written so stop().
html,
body {
overflow: hidden;
}
Did you try this?
I have custom buttons that replaces the browser scrollbar. The idea is so that scrolling oversize elements in a page wouldn't result to a dozen scroll bar on a page.
See: https://jsfiddle.net/bwgxs6ng/
Since I must show some code sample (according to some SO error message), see this:
$('.right').on('click', function(event) {
var target = $(".image-container");
var current_x = target.scrollLeft();
if( target.length ) {
event.preventDefault();
$(target).animate({
scrollLeft: current_x+100
}, 500);
}
});
It's very simple, basically it takes current scroll position of the parent, and add x to it based on the direction that's clicked.
However, going further, I want it to imitate the hold and continuous scroll, but I'm not sure how to do it.
1) What is the mouse hold event called? (OK, this part is answered, it's called MouseDown as someone point out of the duplicate)
2) What is the continuous scrolling called, and how can I do something that'd imitate the browser's continuous scroll?
You can just call .animate() repeatedly (with easing set to linear, for smooth movement) inside your setInterval() callback. Just arrange for the interval to be equal to the animation duration, so that the next animation starts just when the previous one ends.
Or, better yet, make the interval shorter (say, 50 ms or less) and just call .prop() instead of .animate(), effectively performing your own animation. (This is how jQuery implements animation internally, anyway.)
Anyway, here's how I'd rewrite your code to support smooth continuous scrolling:
var speed_x = 0, speed_y = 0;
var timer = null;
var target = $(".image-container");
function scroll() {
if (speed_x == 0 && speed_y == 0) return;
var current_x = target.scrollLeft();
var current_y = target.scrollTop();
target.prop({
scrollLeft: current_x - speed_x,
scrollTop: current_y - speed_y
});
}
$('.control').on('mouseover mouseout', function (event) {
var $this = $(this);
var speed = (event.type == 'mouseover' ? 10 : 0)
if ($this.hasClass('left')) speed_x = +speed;
if ($this.hasClass('right')) speed_x = -speed;
if ($this.hasClass('up')) speed_y = +speed;
if ($this.hasClass('down')) speed_y = -speed;
}).on( 'mousedown', function () {
scroll();
if (timer !== null) clearInterval(timer);
timer = setInterval(scroll, 50);
return false;
});
$(document).on('mouseup', function () {
if (timer !== null) clearInterval(timer);
timer = null;
});
Note how the animation is started and stopped in the mousedown and mouseup handlers, but the direction of movement is set on mouseover and mouseout. This allows you to change the scrolling direction while holding the mouse down, by dragging the cursor from one edge to another.
(For bonus points, add divs with e.g. class="control up left" in the corners of the scroll area, so that holding the mouse down over those corners will allow you to scroll diagonally. The JS code above already supports it.)
you need to set an interval on mousedown, and clear the interval on mouseup, as done in this fiddle for left and right.
The relevant code change is that we removed the click event and replaced it with
$('.left').on('mousedown', function(event) {
... scroll code ...
interval = setInterval(function(){
... scroll code ...
},500);
})
.on('mouseup',function(){clearInterval(interval);});
I currently have this piece of code:
canvas.onmousewheel = scroll;
function scroll(event) {
event.preventDefault();
var mousex = event.clientX - canvas.offsetLeft;
var mousey = event.clientY - canvas.offsetTop;
var wheel = parseInt(event.wheelDelta, 10) / 120; //n or -n
var zoom = 1 + wheel / 2;
[... do some action on canvas ...]
};
Sadly, this doesn't work in Firefox. According to MDN:
Gecko doesn't have a plan to implement this event due to legacy event
type and non-standard.
How can I get my code work for Chrome and Firefox?
edit: The full code is here (one file, about 550 LOC)
You can try the following link
From the page:
onmousewheel event and Firefox's equivalent
var mousewheelevt=(/Firefox/i.test(navigator.userAgent))? "DOMMouseScroll" : "mousewheel" //FF doesn't recognize mousewheel as of FF3.x
if (document.attachEvent) //if IE (and Opera depending on user setting)
document.attachEvent("on"+mousewheelevt, function(e){alert('Mouse wheel movement detected!')})
else if (document.addEventListener) //WC3 browsers
document.addEventListener(mousewheelevt, function(e){alert('Mouse wheel movement detected!')}, false)
I faced this problem and I wrote code to use different events depending on the browser. Certainly jQuery or other frameworks would do it easily, but I am a Vanilla Javascript programmer.
For chrome: onmousewheel and document.body.scrollTop works.
For firefox: onscroll and event.pageY do the same.
if( Browser.chrome){
window.onmousewheel=function(e){
if( document.body.scrollTop > 60){
/* code to run on scrolled window */
} else {
/* code to run when on top */
}
};
} else {
window.onscroll=function(e){
if(e.pageY > 60){
/* code to run on scrolled window */
} else {
/* code to run when on top */
}
};
}
Browsers library available at http://software.sitesbr.net/utils/
I have a div with a javascript touchmove event listener that scrolls the image inside the div horizontally on iOS6 Mobile Safari. I'd like allow vertical scrolling of the page to bubble up to the browser but when this occurs, jQuery.animate no longer works.
I've posted a simplified version of the code that demonstrates the problem at
https://gist.github.com/4047733
The steps I take to recreate the problem are:
Swipe picture left/right and notice how it animates back to the left edge
Touch the picture and scroll the page up/down
Repeat left/right swipe and notice the picture does NOT animate back to the left edge. It appears jQuery animate fails after touchmove occurs without e.preventDefault
Here is the javascript inside jQuery document ready from the gist link above
var el = document.getElementById("swipebox"),
$slider = $('#swipebox').find('img'),
startX, startY, dx, dy,
startLeft,
animateH = false,
animateV = false;
var onTouchStart = function(e) {
startLeft = parseInt($slider.css('left'), 10) || 0;
startX = e.touches[0].pageX;
startY = e.touches[0].pageY;
};
var onTouchMove = function(e) {
dx = e.touches[0].pageX - startX;
dy = e.touches[0].pageY - startY;
if (
animateH ||
(!animateV && Math.abs(dx) > 5)
) {
// prevent default, we are scrolling horizontally,
animateH = true;
$slider.stop().css({'left': startLeft+dx*2});
e.preventDefault();
} else if (Math.abs(dy) > 5) {
// do NOT prevent default, we are scrolling the page vertically
animateV = true;
} else {
// direction of scroll is undetermined at this time
// we've moved less than 5px in any direction
e.preventDefault();
}
return false;
};
var onTouchEnd = function(e) {
$slider.stop().animate({'left': 0}); // animate image back to left
e.preventDefault();
animateH = false;
animateV = false;
};
var onTouchCancel = function(e) {
console.log('onTouchCancel');
};
el.addEventListener('touchstart', onTouchStart, false);
el.addEventListener('touchmove', onTouchMove, false);
el.addEventListener('touchend', onTouchEnd, false);
el.addEventListener("touchcancel", onTouchCancel, false);
Any insight would be greatly appreciated.
This is bug in iOS6. jQuery animate timers fail when scrolling window in iOS6.
Currently there are few workarounds on this:
Create your own timer functions like someone did: https://gist.github.com/3755461
Use CSS3 transition instead of jQuery.animate. This is preffered way - css3 transitions doesn't have such problem. You can use this jquery plugin http://ricostacruz.com/jquery.transit/ to easily manipulate CSS transitions in JavaScript.
I currently have a 1 line div that has no scroll bars, but is scrollable. When I scroll it with my mousewheel, it scrolls from top to bottom, but I would like to make it scroll left to right.
I think I know how to do it with iframes, but is it possible to do it without iframes?
Jsfiddle: http://jsfiddle.net/zfJJX/2/
Thanks!
Add a mouse wheel listener on the div that you want to scroll
In that listener, prevent the default scroll action using e.preventDefault() and e.stopPropagation()
add or subtract from divs scrollLeft property depending on whether it's scroll up or scroll down.
some untested sample code:
$("mydiv").onmousewheel = function(e) {
e.stopPropagation();
e.preventDefault();
var delta = 0;
// normalize the delta
if (event.wheelDelta) {
// IE
delta = event.wheelDelta / 60;
} else if (event.detail) {
// ff and chrome
delta = -event.detail / 2;
}
e.target.scrollLeft += delta;
};