google maps - how to adjust scroll sensitivity - javascript

Recently when using google maps, the scroll sensitivity has been off the chart. On my touchpad, moving my finger about 2mm will go from a scale of about 100ft to seeing the entire globe.
Is there any way to adjust the scroll wheel sensitivity so that this won't be so touchy?
*Edit: using debugger tools in the browser, I was able to find that the zoom was using the wheel event. I tried adding an event listener in the console, but it was never called.
window.addEventListener('wheel', e => {
console.log(e)
})
I'm guessing google already has an event listener which has a stopPropagation. Is there anything I can do in this case to intercept/change these events to reduce the sensitivity?

Since google already has an event listener registered, adding any normal event listener to try to adjust would come after their event listener, and wouldn't do any good, even if they weren't stopping propagation.
Fortunately there is something called "capturing" event listeners, which always happen before regular non-capturing event listeners. (details on capturing can be found in MDN addEventListener docs. So if we register a capturing event listener, we can catch the event before google gets it.
In this case since we just want it to be less sensitive, we can accomplish that by cancelling a bunch of scroll events. After some trial and error, I found that keeping 1 event out of 25 gave the sensitivity I wanted. I parameterized the 25 though, so that it's easy to adjust as needed.
((s) => {
let x = 0;
window.addEventListener('wheel', e => {
if (x++ % s === 0) return;
e.stopImmediatePropagation();
}, { capture: true });
})(25);
You can apply this using something like the greasemonkey plugin, or you can just make it a bookmarklet (create a bookmark, and the URL will be javascript: followed by the above script). Then you just click the bookmarklet once you load google maps, before you scroll.

Related

multiple simultaneous events javascript

This may be a stupid question. I know I am a little green.
I was set with a task of modifying this old, old system's navigation. There are two nav bars. The second has only search buttons. I was asked to remove the second nav bar, and replace it with a drop down that shows the search functions. I am restricted on what I can change due to the age of this system. There are no restrictions on the JS I can write. They are running jQuery 1.11.1, on an Adobe ColdFusion system (two months ago they upgraded from 1.3.2)
First: when the target is clicked, both the mouseenter and the click event trigger. The mouseenter fires first. This causes a problem on a desktop that is visible to the keen viewer, but on mobile, this creates a horriable usability issue. A: From my understanding mouse events do not happen on a mobile device but do for me. And B: since the mouseenter event runs first, it activates the closeDropDown function before the click event is processed. With the closeDropDown running, its .on('click', f(...eventstuff...)) hears the open click that is intended to trigger the openDropDown function, thus the drop down does not open.
Here are the functions. The console.logs are for checking what runs when.
function openDropDown(){
$('div.dropdown').parent().on('click.open mouseenter', function(event){
$subject = $(this).find('.dropdown-menu')
// console.log(event.type, $subject, "first o");
if(!$subject.is(":visible")){
// console.log($subject, 'second o');
$subject.show()
}else {
if(event.type == 'click'){
// console.log('third o');
$subject.toggle()
}
}
closeDropDown($subject)
// console.log('open complete');
})
}
function closeDropDown($x){
// console.log('first c');
$(document).on("click.close",function(e){
// console.log("second c", e.type, "this type");
if(!$(e.target).closest(".dropdown-menu").parent().length){
// console.log("third c");
if($x.is(":visible")){
// console.log('forth c');
$x.hide()
}
}
$(document).off("click.close")
// console.log('complete close');
})
}
openDropDown()
onSearchClick()
I have read a few posts hoping for some help (like this and that
Over all, I know I need to condense my code. I understand a few ways to fix this (add an if(... are we on a mobile device...) or some counter/check that prevents the closeDropDown from running when the dropdown is closed)
I really want to understand the fundamentals of event listeners and why one runs before the other stuff.
Although suggestions on how to fix this are great, I am looking to understand the fundamentals of what I am doing wrong. Any fundamental pointers are very helpful.
Of note: I just read this: .is(':visible') not working. I will be rewriting the code with out the .is('visible').
Other things that might help:
This is the Chrome Dev Tools console when all my console.log(s) are active.
First, click after page load....
Drop down opens and quickly closes.
Second click....
Thanks! All your help is appreciated!
This is a pretty broad question. I'll try to be terse. I don't think ColdFusion should be tagged here, because it seems like it only has to do with HTML/CSS/JS.
Configuring Events
First, I'd like to address the way you have your script configured.
You'd probably benefit from looking at the event handling examples from jquery.
Most people will create events like the following. It just says that on a click for any document element with the ID of "alerter", run the alert function.
// Method 1
$(document).on(click, "#alerter", function(event){
alert("Hi!");
});
OR
// Method 2
$(document).on("click", "#alerter", ClickAlerter);
function ClickAlerter(event) {
alert("Hi!");
}
Both methods are totally valid. However, it is my opinion that the second method is more readable and maintainable. It separates event delegation from logic.
For your code, I would highly recommend removing the mixing of event assignment and logic. (It removes at least one layer of nesting).
Incidentally, your event listeners don't appear to be configured correctly. See the correct syntax and this example from jQuery.
$( "#dataTable tbody" ).on( "click", "tr", function() {
console.log( $( this ).text() );
});
Regarding Multiple Events
If you have multiple event listeners on an object, then they will be fired in the order which they are registered. This SO question already covers this and provides an example.
However, this doesn't mean that a click will occur before a mouseenter. Because your mouse has to literally enter the element to be able to click it, the event for mouseenter is going to be fired first. In other words, you have at least 2 factors at play when thinking about the order of events.
The order in which the browser will fire the events
The order in which they were registered
Because of this, there isn't really such a thing as "simultaneous" events, per se. Events are fired when the browser wants to fire them, and they will go through events and fire the matches in the order that you assigned them.
You always have the option of preventDefault and stopPropagation on these kinds of events if you want to alter the default event behavior. That will stop the browser's default action, and prevent the event from bubbling up to parent elements, respectively.
Regarding Mobile Mouse Events
Mouse events absolutely happen on mobile devices, and it's not safe to assume they don't. This article covers in great depth the scope of events that get fired. To quote:
"[Y]ou have to be careful when designing more advanced touch interactions: when the user uses a mouse it will respond via a click event, but when the user touches the screen both touch and click events will occur. For a single click the order of events is:
touchstart
touchmove
touchend
mouseover
mousemove
mousedown
mouseup
click
I think you would benefit from reading that article. It covers common problems and concepts regarding events in mobile and non-mobile environments. Again, a relevant statement about your situation:
Interestingly enough, though, the CSS :hover pseudoclass CAN be triggered by touch interfaces in some cases - tapping an element makes it :active while the finger is down, and it also acquires the :hover state. (With Internet Explorer, the :hover is only in effect while the user’s finger is down - other browsers keep the :hover in effect until the next tap or mouse move.)
An Example
I took all these concepts and made an example on jsFiddle to show you some of these things in action. Basically, I'm detecting whether the user is using a touchscreen by listening for the touchstart event and handling the click differently in that case. Because I don't have your HTML, I had to make a primitive interface. These are the directives:
We need to determine if the user has a touchscreen
When the user hovers over the button, the menu should appear
On a mobile device, when a user taps the button, the menu should appear
We need to close the menu when the user clicks outside of the button
Leaving the button should close the menu (mobile or otherwise)
As you will see, I created all my events in one place:
$(document).on("mouseover", "#open", $app.mouseOver);
$(document).on("mouseout", "#open", $app.mouseOut);
$(document).on("click", "#open", $app.click);
$(document).on("touchstart", $app.handleTouch);
$(document).on("touchstart", "#open", $app.click);
I also created an object to wrap all the logic in, $app which gives us greater flexibility and readability down the road. Here's a fragment of it:
var $app = $app || {};
$app = {
hasTouchScreen: false,
handleTouch:function(e){
// fires on the touchstart event
$app.hasTouchScreen = true;
$("#hasTouchScreen").html("true");
$(document).off("touchstart", $app.handleTouch);
},
click: function(e) {
// fires when a click event occurrs on the button
if ($app.hasTouchScreen) {
e.stopPropagation();
e.preventDefault();
return;
}
// since we don't have a touchscreen, close on click.
$app.toggleMenu(true);
},
touch: function(e) {
// fires when a touchstart event occurs on the button
if ($("#menu").hasClass("showing")) {
$app.toggleMenu(true);
} else {
$app.toggleMenu();
}
}
};

How to identify if a mouseover event object came from a touchscreen touch?

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>

Display context menu over HERE map

Using HERE maps, I would like to display a context menu on right-click (or long-touch).
The developers guide lists the valid mouse/touch events as:
pointerdown
pointerup
pointermove
pointerenter
pointerleave
pointercancel
dragstart
drag
dragend
tap
dbltap
which implies I have to look into checking buttons on tap event but the API documentation also describes a ContextMenuEvent object, stating:
ContextMenuEvent should be fired, when a user right-clicks or longpresses on a map object.
Which of the events listed above constitutes a "right-click" or "longpress" event, receiving this ContextMenuEvent object?
There is a functioning example of a Context Menu on top of a HERE map here, but there is no mention of this in the current documentation and it appears to be using an older version of the API. Has the ability to produce context menus been removed?
On a whim I tried attaching to the event type contextmenu and it WORKED! Apparently this is just missing from their documentation.
contextmenu
There's an alternative way to handle right-clicks if you are already listening for a "tap" event. In the originalEvent property on the tap event object, HERE Maps adds a which property to the PointerEvent object, which seems to indicate which button was used to fire the event. This value is 1 for left-clicks, 2 for middle-clicks and 3 for right-clicks.
With this in mind, you can modify your tap event to handle different mouse buttons by doing something similar to the below:
map.addEventListener("tap", function (evt) {
switch (evt.originalEvent.which) {
case 1: // Left-click
handleLeftClick(evt);
break;
case 3: // Right-click
handleRightClick(evt);
break;
default:
// Do something else for other buttons, if you want
break;
}
});
Keep in mind that which is not part of the PointerEvent interface, so HERE Maps may change or break this behavior in the future.

Flex capture all mouse clicks on application

I want to capture every mouse event and I tried to add event listeners to FlexGlobals.topLevelApplication. However there are some cases (like Flex's Menu class) when the clicks aren't captured - probably somewhere the event propagation is stopped. For example in SystemManager.as I found this:
addEventListener(MouseEvent.MOUSE_DOWN, mouseEventHandler, true, 1000);
...which seems to override my listener. Also I tried to add Listeners with priority int.MAX_VALUE but with no success.
So my question is - how can I capture all mouse clicks, without worrying about my events being stopped somewhere? Maybe some javascript hack? Or maybe to add the event listeners somewhere where there is no chance for them to be canceled? Thanks.
You could try adding the event handler to stage with capture:
systemManager.stage.addEventListener(MouseEvent.MOUSE_DOWN, mouseEventHandler, true, Integer.MAX_VALUE);

Detect if mouse is over an element when page loads with Javascript

I have an image that I want to have trigger certain behaviors when the mouse is over, I have a mouseover and mouseout method, but if you happen to have your mouse over the image when the page loads, the mouseover method never fires until you leave the image and come back over it.
Is there a way to detect if the mouse is over an element on the fly without the mouse having to be off of the element and then come over the element to trigger the JS mouseover event? Like is there a document.getElementById("blah").mouseIsOver() type function in Javascript?
I believe this is possible without any action from the user. When your page loads, bind the mouseover event to your image and hide your image (i.e. using CSS display:none). Use setTimeout() to show it again in a few milliseconds (10 should be enough). The even should be fired.
If you don't want to cause the 'flick' effect on your image, you may try using some temporary element instead, attaching event to it, and delegating the event onto your image.
I have no idea if this is cross-browser solution, but it worked from my Firefox 3.0 console ;)
You could use the mousemove event. That would trigger anytime the user moves a mouse; so the only instance of the trigger not firing would be if the user does not move the mouse at all, which should be rare.
The only problem with this is that the event would fire anytime the mouse would move over your image, so you would get a LOT of those events while over the component. What you would probably need to do is implement some sort of flag within your method when the event fires. You turn on the flag when the event first fires, and you turn it off when you leave the component.
This is less than ideal, but I think this will probably satisfy your problem scenario. The following is some quick pseudo code on what that solution might look like, I think it should work.
<img src="blah.png" onmousemove="JavaScript:triggerOn(event)" onmouseout="JavaScript:triggerOff(event)"/>
...
<script type='text/javascript'>
var TriggerActive = false;
function triggerOn(e){
e = e||window.e;
if( !TriggerActive){
TriggerActive = true;
// Do something
} else {
// Trigger already fired, ignore this event.
}
}
function triggerOff(e){
e = e||window.e;
if(TriggerActive)
TriggerActive = false;
}
</script>
You can find some great mouse event information including browser compatibility notes here.
Use document.querySelectpor and onload/onready events.
var a = document.querySelector('#a:hover');
if (a) {
// Mouse cursor is above a
}
else {
// Mouse cursor is outside a
}
There is no way to get the mouse coordinates aside from listening for mouse events, namely mousemove, mouseover etc. However, these events are very sensitive in the sense that moving the cursor by just one pixel is enough to trigger them, so having the cursor hover over your image while perfectly still should be somewhat unusual.

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