Related
On virtually all current browsers (extensive details from patrickhlauke on github, which I summarised in an SO answer, and also some more info from QuirksMode), touchscreen touches trigger mouseover events (sometimes creating an invisible pseudo-cursor that stays where the user touched until they touch elsewhere).
Sometimes this causes undesirable behaviour in cases where touch/click and mouseover are intended to do different things.
From inside a function responding to a mouseover event, that has been passed the event object, is there any way I can check if this was a "real" mouseover from a moving cursor that moved from outside an element to inside it, or if it was caused by this touchscreen behaviour from a touchscreen touch?
The event object looks identical. For example, on chrome, a mouseover event caused by a user touching a touchscreen has type: "mouseover" and nothing I can see that would identify it as touch related.
I had the idea of binding an event to touchstart that alters mouseover events then an event to touchend that removes this alteration. Unfortunately, this doesn't work, because the event order appears to be touchstart → touchend → mouseover → click (I can't attach the normalise-mouseover function to click without messing up other functionality).
I'd expected this question to have been asked before but existing questions don't quite cut it:
How to handle mouseover and mouseleave events in Windows 8.1 Touchscreen is about C# / ASP.Net applications on Windows, not web pages in a browser
JQuery .on(“click”) triggers “mouseover” on touch device is similar but is about jQuery and the answer is a bad approach (guessing a hard-coded list of touchscreen user agents, which would break when new device UAs are created, and which falsely assumes all devices are mouse or touchscreen)
Preventing touch from generating mouseOver and mouseMove events in Android browser is the closest I could find, but it is only about Android, is about preventing not identifying mouseover on touch, and has no answer
Browser handling mouseover event for touch devices causes wrong click event to fire is related, but they're trying to elumate the iOS two-tap interaction pattern, and also the only answer makes that mistake of assuming that touches and mouse/clicks are mutually exclusive.
The best I can think of is to have a touch event that sets some globally accessible variable flag like, say, window.touchedRecently = true; on touchstart but not click, then removes this flag after, say, a 500ms setTimeout. This is an ugly hack though.
Note - we cannot assume that touchscreen devices have no mouse-like roving cursor or visa versa, because there are many devices that use a touchscreen and mouse-like pen that moves a cursor while hovering near the screen, or that use a touchscreen and a mouse (e.g. touchscreen laptops). More details in my answer to How do I detect whether a browser supports mouseover events?.
Note #2 - this is not a jQuery question, my events are coming from Raphael.js paths for which jQuery isn't an option and which give a plain vanilla browser event object. If there is a Raphael-specific solution I'd accept that, but it's very unlikely and a raw-javascript solution would be better.
Given the complexity of the issue, I thought it was worth detailing the issues and edge cases involved in any potential solution.
The issues:
1 - Different implementations of touch events across devices and browsers. What works for some will definitely not work for others. You only need to glance at those patrickhlauke resources to get an idea of how differently the process of tapping a touch-screen is currently handled across devices and browsers.
2 - The event handler gives no clue as to its initial trigger. You are also absolutely right in saying that the event object is identical (certainly in the vast majority of cases) between mouse events dispatched by interaction with a mouse, and mouse events dispatched by a touch interaction.
3 - Any solution to this problem which covers all devices could well be short-lived as the current W3C Recommendations do not go into enough detail on how touch/click events should be handled (https://www.w3.org/TR/touch-events/), so browsers will continue to have different implementations. It also appears that the Touch Events standards document has not changed in the past 5 years, so this isn't going to fix itself soon. https://www.w3.org/standards/history/touch-events
4 - Ideally, solutions should not use timeouts as there is no defined time from touch event to mouse event, and given the spec, there most probably won't be any time soon. Unfortunately, timeouts are almost inevitable as I will explain later.
A future solution:
In the future, the solution will probably be to use Pointer Events instead of mouse / touch events as these give us the pointerType (https://developer.mozilla.org/en-US/docs/Web/API/Pointer_events), but unfortunately we're not there yet in terms of an established standard, and so cross-browser compatibility (https://caniuse.com/#search=pointer%20events) is poor.
How do we solve this at the moment
If we accept that:
You can't detect a touchscreen (http://www.stucox.com/blog/you-cant-detect-a-touchscreen/)
Even if we could, there's still the issue of non-touch events on a touch capable screen
Then we can only use data about the mouse event itself to determine its origin. As we've established, the browser doesn't provide this, so we need to add it ourselves. The only way to do this is using the touch events which are triggered around the same time as the mouse event.
Looking at the patrickhlauke resources again, we can make some statements:
mouseover is always followed by the click events mousedown mouseup and click - always in that order. (Sometimes separated by other events). This is backed up by the W3C recommendations: https://www.w3.org/TR/touch-events/.
For most devices / browsers, the mouseover event is always preceded by either pointerover, its MS counterpart MSPointerOver, or touchstart
The devices / browsers whose event order begins with mouseover have to be ignored. We can't establish that the mouse event was triggered by a touch event before the touch event itself has been triggered.
Given this, we could set a flag during pointerover, MSPointerOver, and touchstart, and remove it during one of the click events. This would work well, except for a handfull of cases:
event.preventDefault is called on one of the touch events - the flag will never be unset as the click events will not be called, and so any future genuine click events on this element would still be marked as a touch event
if the target element is moved during the event. The W3C Recommendations state
If the contents of the document have changed during processing of the
touch events, then the user agent may dispatch the mouse events to a
different target than the touch events.
Unfortunately this means that we will always need to use timeouts. To my knowledge there is no way of either establishing when a touch event has called event.preventDefault, nor understanding when the touch element has been moved within the DOM and the click event triggered on another element.
I think this is a fascinating scenario, so this answer will be amended shortly to contain a recommended code response. For now, I would recommend the answer provided by #ibowankenobi or the answer provided by #Manuel Otto.
What we do know is:
When the user uses no mouse
the mouseover is directly (within 800ms) fired after either a touchend or a
touchstart (if the user tapped and held).
the position of the mouseover and the touchstart/touchend are identical.
When the user uses a mouse/pen
The mouseover is fired before the touch events, even if not, the position of the mouseover will not match the touch events' position 99% of time.
Keeping these points in mind, I made a snippet, which will add a flag triggeredByTouch = true to the event if the listed conditions are met. Additionally you can add this behaviour to other mouse events or set kill = true in order to discard mouseevents triggered by touch completely.
(function (target){
var keep_ms = 1000 // how long to keep the touchevents
var kill = false // wether to kill any mouse events triggered by touch
var touchpoints = []
function registerTouch(e){
var touch = e.touches[0] || e.changedTouches[0]
var point = {x:touch.pageX,y:touch.pageY}
touchpoints.push(point)
setTimeout(function (){
// remove touchpoint from list after keep_ms
touchpoints.splice(touchpoints.indexOf(point),1)
},keep_ms)
}
function handleMouseEvent(e){
for(var i in touchpoints){
//check if mouseevent's position is (almost) identical to any previously registered touch events' positions
if(Math.abs(touchpoints[i].x-e.pageX)<2 && Math.abs(touchpoints[i].y-e.pageY)<2){
//set flag on event
e.triggeredByTouch = true
//if wanted, kill the event
if(kill){
e.cancel = true
e.returnValue = false
e.cancelBubble = true
e.preventDefault()
e.stopPropagation()
}
return
}
}
}
target.addEventListener('touchstart',registerTouch,true)
target.addEventListener('touchend',registerTouch,true)
// which mouse events to monitor
target.addEventListener('mouseover',handleMouseEvent,true)
//target.addEventListener('click',handleMouseEvent,true) - uncomment or add others if wanted
})(document)
Try it out:
function onMouseOver(e){
console.log('triggered by touch:',e.triggeredByTouch ? 'yes' : 'no')
}
(function (target){
var keep_ms = 1000 // how long to keep the touchevents
var kill = false // wether to kill any mouse events triggered by touch
var touchpoints = []
function registerTouch(e){
var touch = e.touches[0] || e.changedTouches[0]
var point = {x:touch.pageX,y:touch.pageY}
touchpoints.push(point)
setTimeout(function (){
// remove touchpoint from list after keep_ms
touchpoints.splice(touchpoints.indexOf(point),1)
},keep_ms)
}
function handleMouseEvent(e){
for(var i in touchpoints){
//check if mouseevent's position is (almost) identical to any previously registered touch events' positions
if(Math.abs(touchpoints[i].x-e.pageX)<2 && Math.abs(touchpoints[i].y-e.pageY)<2){
//set flag on event
e.triggeredByTouch = true
//if wanted, kill the event
if(kill){
e.cancel = true
e.returnValue = false
e.cancelBubble = true
e.preventDefault()
e.stopPropagation()
}
return
}
}
}
target.addEventListener('touchstart',registerTouch,true)
target.addEventListener('touchend',registerTouch,true)
// which mouse events to monitor
target.addEventListener('mouseover',handleMouseEvent,true)
//target.addEventListener('click',handleMouseEvent,true) - uncomment or add others if wanted
})(document)
a{
font-family: Helvatica, Arial;
font-size: 21pt;
}
Click me
According to https://www.html5rocks.com/en/mobile/touchandmouse/
For a single click the order of events is:
touchstart
touchmove
touchend
mouseover
mousemove
mousedown
mouseup
click
So you might be able to set some arbitrary boolean isFromTouchEvent = true; in onTouchStart() and isFromTouchEvent = false; in onClick() and check for that inside of onMouseOver(). This doesn't work very well since we're not guaranteed to get all those events in the element that we're trying to listen on.
I usually have couple of general schemes which I use for this, one of them uses a manual principle of setTimeout to trigger a property. I will explain this one here, but first try to reason about using touchstart, touchmove and touchend on touch devices and use mouseover on destop.
As you know, calling event.preventDefault (event has to be not passive for this to work with touchstart) in any of the touchevents will cancel the subsequent mousecalls so you do not need to deal with them. But in case this is not what you want, here is what I use sometimes (I refer as "library" to your dom manipulation library, and "elem" as your element):
with setTimeout
library.select(elem) //select the element
.property("_detectTouch",function(){//add a _detectTouch method that will set a property on the element for an arbitrary time
return function(){
this._touchDetected = true;
clearTimeout(this._timeout);
this._timeout = setTimeout(function(self){
self._touchDetected = false;//set this accordingly, I deal with either touch or desktop so I can make this 10000. Otherwise make it ~400ms. (iOS mouse emulation delay is around 300ms)
},10000,this);
}
}).on("click",function(){
/*some action*/
}).on("mouseover",function(){
if (this._touchDetected) {
/*coming from touch device*/
} else {
/*desktop*/
}
}).on("touchstart",function(){
this._detectTouch();//the property method as described at the beginning
toggleClass(document.body,"lock-scroll",true);//disable scroll on body by overflow-y hidden;
}).on("touchmove",function(){
disableScroll();//if the above overflow-y hidden don't work, another function to disable scroll on iOS.
}).on("touchend",function(){
library.event.preventDefault();//now we call this, if you do this on touchstart chrome will complain (unless not passive)
this._detectTouch();
var touchObj = library.event.tagetTouches && library.event.tagetTouches.length
? library.event.tagetTouches[0]
: library.event.changedTouches[0];
if (elem.contains(document.elementFromPoint(touchObj.clientX,touchObj.clientY))) {//check if we are still on the element.
this.click();//click will never be fired since default prevented, so we call it here. Alternatively add the same function ref to this event.
}
toggleClass(document.body,"lock-scroll",false);//enable scroll
enableScroll();//enableScroll
})
Another option without setTimeout is to think mousover is counter to touchstart and mouseout counter to touchend. So former events (the touch events) will set a property, if the mouse events detect that property then they do not fire and reset the property to its initial value and so on. In that case something along these lines will also do:
without setTimeout
....
.on("mouseover",function(dd,ii){
if (this._touchStarted) {//touch device
this._touchStarted = false;//set it back to false, so that next round it can fire incase touch is not detected.
return;
}
/*desktop*/
})
.on("mouseout",function(dd,ii){//same as above
if(this._touchEnded){
this._touchEnded = false;
return;
}
})
.on("touchstart",function(dd,ii){
this._touchStarted = true;
/*some action*/
})
.on("touchend",function(dd,ii){
library.event.preventDefault();//at this point emulations should not fire at all, but incase they do, we have the attached properties
this._touchEnded = true;
/*some action*/
});
I removed a lot of details but I guess this is the main idea.
You can use modernizr for that! I just tested this on a local development server and it works.
if (Modernizr.touch) {
console.log('Touch Screen');
} else {
console.log('No Touch Screen');
}
So I would start there?
Pointer Events are widely supported now. So now we can use pointerenter and check event.pointerType:
const element = document.getElementById("hoverableElement")
element.addEventListener("pointerenter", (event) => {
if (event.pointerType === "mouse") {
alert("Hovered")
}
})
<div id="hoverableElement">Trigger on hover, but not on touch</div>
Does the jQuery Mobile Tap corresponds to adding an event listener to an element like this:
myElement.addEventListener("touchstart", touchStartHandler, false);
If so, what about the remaining normal events such as touchmove, touchend and so on? I mean what is their equivalent in jQuery Mobile?
Thank you for guiding me.
Internally tap makes use of vclick.
If you don't find an event in this list, they aren't exposed with the same name: https://api.jquerymobile.com/category/events/
This means, for example: if you need to handle touchstart, touchend and touchmove, as normally is, you will probably end up to use the set of virtualized mouse event handler: vmousedown, vmousemove, vmouseup and vclick but you may need to handle the status of the pointer (mouse or finger) by yourself. Do not forget to handle vmousecancel.
Moreover, you should note that there is a delay to wait for some events.
Following is a short extract for you, from the jQuery Mobile documentation with some critical concepts for touch devices (mobile or modern hybrid laptops) to pay attention to:
Webkit based browsers synthesize mousedown, mouseup, and click events
roughly 300ms after the touchend event is dispatched.
The jQuery Mobile taphold triggers after 750ms.
After 1500ms, then it is not a touch event. Scroll, TouchMove and
TouchEnd events use this. The block list is cleared.
We recommend using click instead of vclick anytime the action being
triggered has the possibility of changing the content underneath the
point that was touched on screen. This includes page transitions and
other behaviors such as collapse/expand that could result in the
screen shifting or content being completely replaced.
Have a nice day
I dont know if is exactly the same way they do the handle, but both of they wait for an action and then execute funciton.
in jquery mobile you can do
$("p").on("taphold",function(){
$(this).hide();
});
and
$(function(){
$( "div.box" ).bind( "tap", tapHandler );
function tapHandler( event ){
$( event.target ).addClass( "tap" );
}
});
list of events https://api.jquerymobile.com/category/events/
I am building an iPad application which is essentially a series of slides.
When I've finished reading a slide I am able to swipe to the next slide *(using Zepto's swipe) which changes the window.location to the next slide. (the swipe event is bound to the window.body as it needs to work on the whole page)...
Here is the problem: some slides have interactive elements such as buttons, draggable items etc. The problem is that the swipe event is triggered when using some of these interactive elements.
Does anyone know of a way to prevent swipe from triggering in these instances? Perhaps settings a sensitivity etc?
I'm stumped...
Best wishes and many thanks!!
The way Zepto manages touch events is it binds listeners to the touchstart, touchend, and touchmove events on document.body. It then performs calculations on what event to send and triggers an event on the element that received the touchstart event. This event then bubbles up through the DOM tree evoking the listeners of each element.
This gives us two ways of preventing swipe events:
First, you could do something like:
$('#my-child-element').bind('touchstart touchend touchup', function(event) {
event.stopPropagation();
});
When your child element receives one a touch event, it will prevent it from propagating to parent elements, most importantly the body tag. This prevents the Zepto touch processor from doing anything, blocking swipe, tap, singleTap, longTap, and doubleTap events from occurring while operating in that element.
Because swipe events also bubble, you could also just prevent those specific events from bubbling to your element that listens to page change swipes:
$('#my-child-element').bind('swipeLeft swipeRight', function(event) {
event.stopPropagation();
});
This will allow you to still receive the Zepto generated events inside your child element but not outside. Zepto tap events will also still work for all elements within your child.
Fiddle here: http://jsfiddle.net/bnickel/dUuUd/
Hope "excludedElements" method will help you, like below.
$(".block").swipe({
swipe: function (event, direction, distance, duration, fingerCount, fingerData) {
},
excludedElements: ".link, a",
threshold: 0
});
I build a web mobile game, it runs on browsers (PC/Mobile).
Do I need to use the touchmove or not?
How can I run the touchmove event like the mousemove event?
For parity between desktop and touch you have the following equivalences:
mousedown === touchstart
mousemove === touchmove
mouseup === touchend
Thus if you handle mousedown, mousemove and mouseup then you don't need to handle the corresponding equivalent events under touch. The same handlers should be executing.
Except on the ipad -- where mouse hover, mouse down, mouse up and click are all triggered... except if you change anything in mouse hover .. then nothing else gets triggered.... very annoying...more details see http://sitr.us/2011/07/28/how-mobile-safari-emulates-mouse-events.html
you can use both in one component (w.r.t react)
for eg:
<component onMouseMove={handleMouseMove} onTouchMove={handleMouseMove} />
on the bases of screen which is being used react will automatically switch either option of mouse or touch
or you can also use
("ontouchstart" in document.documentElement)
it gives true for touch screen device and vice versa
ref: https://codepen.io/tteske/pen/KKwxOxp
In doing a single page Javascript app with interactive DOM elements I've found that the "mouseover-mousemove-mousedown-mouseup-click" sequence happens all in a bunch after the "touchstart-touchmove-touchend" sequence of events.
I've also found that it is possible to prevent the "mouse*-click" events from happening by doing an "event.preventDefault()" during the touchstart event, but only then, and not during the touchmove and touchend. This is a strange design, because because it is not possible to know during the touchstart yet whether the user intents to drag or swipe or just tap/click on the item.
I ended up setting up a "ignore_next_click" flag somewhere tied to a timestamp, but this is obviously not very clean.
Does anybody know of a better way of doing this, or are we missing something?
Note that while a "click" can be recognized as a "touchstart-touchend" sequence (ie no "touchmove"), there are certain things, such as keyboard input focus, that can only happen during a proper click event.
Just prevent the touchend event. It will let the browser scroll the page when you touch the element but won't let it emit artificial mouse events.
element.addEventListener('touchend', event => {
event.preventDefault();
});
I've run into similar problems making cross-platform HTML5/JS apps. The only real answer for me was to preventDefault on the touch events, and actually manage the touch states and fire click, drags, etc. events on my own according to my logic. This sounds much much more daunting than it really is, but the mimicked click/mouse events work perfectly on most mobile browsers.
Click and the extra mouse sequence are all there for your convenience (and compatibility). My rule of thumb- if it's for your convenience but it's inconvenient, best kill it.
As far as the input boxes, they only need the touchend events. I've killed click/mouse events and was still able to let mobile browsers respond correctly to touches on inputs. If it's still giving you issues, you can modify the event handler to only supress events on non-inputs:
function touchHandler(event) {
var shouldIgnore = event.target != null
&& ( event.target.tagName.toLowerCase() == "input" || event.target.tagName.toLowerCase() == "textarea" );
if(!shouldIgnore) e.preventDefault();
}
I've made a solution myself, since I have not found a sufficient solution elsewhere:
var isTouch = ('ontouchstart' in window);
function kill(type){
window.document.body.addEventListener(type, function(e){
e.preventDefault();
e.stopPropagation();
return false;
}, true);
}
if( isTouch ){
kill('mousedown');
kill('mouseup');
kill('click');
kill('mousemove');
}
The check of isTouch lets things work as normal on mouse-input devices but kills the emulated events on Safari/iOS. The trick is to use useCapture = true in the call to addEventListener so we scoop up all the mouse events in the page without hacking the code all over the web app. See the docs for the function here: https://developer.mozilla.org/en-US/docs/DOM/EventTarget.addEventListener?redirectlocale=en-US&redirectslug=DOM%2Felement.addEventListener
Edit:
Now that libraries for handling this issue are better, you can just use something like Fastclick as an alternative (https://github.com/ftlabs/fastclick).
If you have to support devices which support both mouse and touch, another solution is to use a capture event listener which stops all mouse events which occur either
within a delay after the touch event
at the same position as the touch event
on the same target element as the touch event
The information (time, position or target element) of the touch event can be recorded in another capture event listener.
Wrapping your mouse-only code in a Window.matchesMedia function is the cleanest way I found.
if (window.matchMedia('(hover: hover), (any-hover: hover), (-moz-touch-enabled: 0)').matches) {
el.addEventListener('mouseover', ev => {
// mouse handler, no simulated hover
}
}
This works for preventing simulated hovers but will likely prevent simulated clicks, too.
Note: -moz-touch-enabled part required on Firefox as of version 58.
This solution allows you to listen for PointerEvents if they exist, followed by TouchEvents if they exist, followed by MouseEvents if neither of the other two exist. Mobile Safari will still raise both touchstart and mousedown, but you'll only be listening for touchstart.
if (window.PointerEvent) { /* decent browsers */
etouch.addEventListener('pointerdown', (e) => {
console.log('pointerdown');
});
}
else if (window.TouchEvent) { /* mobile Safari */
etouch.addEventListener('touchstart', (e) => {
console.log('touchstart');
});
}
else { /* desktop Safari */
etouch.addEventListener('mousedown', (e) => {
console.log('mousedown');
});
}
Using 'pointerwhatever' instead of 'mousewhatever' seems to work fine on current browsers (2019).
i.e. they invented a way of having the same code for all the entry devices.
Creating Fast Buttons for Mobile Web Applications has their solution to the problem.
Also beware that when using IE10 preventDefault() doesn't stop the ghost/synthetic/emulated mouse events after a MSPointerDown event, so a true cross-browser solution is harder.
You could try to quit the function on "click", "mousedown" or "mouseup" events when the device supports touch events.
use.addEventListener("click",function(e){
// EXIT FUNCTION IF DEVICE SUPPORTS TOUCH EVENTS
if ("ontouchstart" in document.documentElement) return false;
// YOURMOUSEONLY CODE HERE
});
Add an event listener to touchstart that adds attribute data-touched to the element. Add another event listener to click that checks for data-touched. If it's there, prevent default and remove it. Here's some JS from my implementation.
var menuLinks = document.querySelectorAll('#my-nav>li>a');
for (var i = 0; i < menuLinks.length; i++) {
var menuLink = menuLinks[i];
menuLink.addEventListener('touchstart', function () {
menuLink.setAttribute('data-touched', '');
});
menuLink.addEventListener('click', function (event) {
if (menuLink.hasAttribute('data-touched')) {
menuLink.removeAttribute('data-touched');
event.preventDefault();
}
});
pointer... events have a pointerType property that mouse... events lack. You can use this property to detect and ignore events that were generated by touch rather than by a mouse.
Before:
window.addEventListner('mousemove', (e) => {
/* No way to tell if this event came from a mouse or a finger */
console.log(':(');
});
After:
window.addEventListner('pointermove', (e) => {
if (e.pointerType !== 'mouse') return;
/* This event definitely came from a mouse */
console.log(':)');
});
You can take advantage of this property just by replacing your mouse... event listeners with pointer... listeners. pointer... events are well-supported in modern browsers (going back at least three years).