Get event inside of EventListener - javascript

The following code doesn't work:
slider.prototype.onTransitionEnd = function() {
var self = this;
self.slideElement.addEventListener(self.startEvent, function() { self.onTouchStart(/* e, event or what? */ }, false);
}
slider.prototype.onTouchStart = function(e) {
alert(e);
//HERE I NEED THE EVENT, HOW CAN I GET THIS?
}
The problem is, that I cannot access to the event inside the function onTouchStart.
By default, the event automatically transferred:
function onTransitionEnd() {
slide.addEventListener(startEvent, onTouchStart, false);
}
function onTouchStart(e) {
alert(e) /* IT WORK'S! */
}
But how does it work in my example?

You seem to be missing a parenthesis. Could that be what's wrong?
slider.prototype.onTransitionEnd = function() {
var self = this;
self.slideElement.addEventListener(self.startEvent, function() { self.onTouchStart(/* e, event or what? */) }, false);
}
slider.prototype.onTouchStart = function(e) {
alert(e);
//HERE I NEED THE EVENT, HOW CAN I GET THIS?
}

Related

How to detect DOM modification event

I have been trying to get listen to DOM change event for a several hours, however still cannot get it working.
I need to detect events that are showed in Chrome Debug Tools as changes displayed as pink color.
Here is what I've tried
function listenForDomModified(node, listener) {
node.addEventListener("DOMSubtreeModified", listener, false);
var iframes = node.getElementsByTagName("iframe");
for (var i = 0, len = iframes.length, doc; i < len; ++i) {
// Catch and ignore errors caused by iframes from other domains
try {
doc = iframes[i].contentDocument || iframes[i].contentWindow.document;
doc.addEventListener("DOMSubtreeModified", listener, false);
} catch (ex) {}
}
}
var findElements = function () {
elements.iframeBlock = $(SELECTOR.IFRAME_BLOCK);
};
var onIframeChange = function (e) {
console.log("CHANGE !!!");
alert("DOM CHANGES");
};
var setListeners = function () {
listenForDomModified(elements.iframeBlock[0],onIframeChange);
elements.iframeBlock.bind('DOMSubtreeModified', function(e) {
if (e.target.innerHTML.length > 0) {
alert("ON CHANGE");
}
alert("ON CHANGE");
});
//elements.iframeBlock.change(onIframeChange);
};
Please note, I tried these methods separately.
But still cannot get my function called. However Chrome displays these changes.
I would be grateful for any help.
Thanks
Have you tried
$(document).on('change', function () { /*code*/ });
Try this jQuery approach:
$("iframe").contents().find('body').on("change", function() {
alert("DOM CHANGES");
});
not tested...

how to pass self(this) to addEventListener without breaking removeEventListener?

I'm adding checkboxchange event to checkbox here. (moveButton is a checkBox because im using CSS checkbox hack)
var self = this;
this.moveButton.addEventListener("change", function(e){self.toggleMove(e, self)});
if the checkbox is checked it adds an eventListener to body.document
DR.prototype.toggleMove = function(e, self){
if(self.moveButton.checked){
document.body.addEventListener("click", function bodyEvent(e){self.removeableEventHandler(e, self)}, false);
}else{
console.log("unchecked");
document.body.removeEventListener("click", function bodyEvent(e){self.removeableEventHandler(e, self)}, false);
}
}
if i don't wrap self.removeableEventHandler in a function i am unable to attach self to the function, but when i wrap it in a function i will be unable to remove the event when the checkbox is unchecked.
DR.prototype.removeableEventHandler = function(e, self){
console.log(e.clientX, e.clientY);
self.ele.style.top = e.clientY + "px";
self.ele.style.left = e.clientX + "px";
};
So it seems to be like I'm having a bit of a scope conundrum here. Not sure how to fix it. I'm trying to make a form moveable when the checkbox is checked and then removing the move event when the checkbox is unchecked.
removeEventListener works by passing the original function reference. If you pass a copy it wont work.
You can do:
DR.prototype.toggleMove = (function () {
var boundBodyEvent;
function bodyEvent(e) {
this.removeableEventHandler(e);
}
return function (e) {
if (this.moveButton.checked) {
boundBodyEvent= bodyEvent.bind(this);
document.body.addEventListener("click", boundBodyEvent, false);
} else {
document.body.removeEventListener("click", boundBodyEvent, false);
}
};
}());
I don't think you need to pass self around, that seems strange to me. I'm using bind to override the this in bodyEvent to refernce your DR instance instead of the DOM Element.
I'm also using immediate invocation to avoid having to put the bodyEvent in the global scope.
Alternatively, you could also not bother removing the event listener and have a switch inside the event listener:
DR.prototype.init = function () {
var self = this;
document.body.addEventListener("click", function (e) {
if (self.moveButton.checked) {
self.removeableEventHandler(e);
}
}, false);
}
removeEventListener callbak function need to be reference to the same function as in addEventListener, try this:
function bodyEvent(e) {
self.removeableEventHandler(e, self);
}
DR.prototype.toggleMove = function(e, self) {
if (self.moveButton.checked) {
document.body.addEventListener("click", bodyEvent, false);
} else {
console.log("unchecked");
document.body.removeEventListener("click", bodyEvent, false);
}
};

removeEventListener from body not working

I'm trying to remove an event listener after a function has been called. But the event listener for "keyup" stays attached to the body, no matter what I try. What is wrong with the code?
function displayImage() {
//this is a simplified version of the code
var outerFrame = document.createElement('div');
outerFrame.className = 'popup-outer';
document.body.appendChild(outerFrame);
document.body.addEventListener('keyup', hideImage.bind(outerFrame), false);
}
function hideImage(e) {
if (e.keyCode === 27) {
// this doesn't work, it stays attached to the body element
document.body.removeEventListener('keyup', hideImage, false);
document.body.removeChild(this);
}
e.preventDefault();
}
It's because technically
hideImage.bind(outerFrame)
is different from
hideImage
because the first one returns a copy of the function hideImage.
So when you try to unbind hideImage, the event manager does not find it because it registred a copy of it and thus nothing is removed :-/.
EDIT :
In your case, I guess you have no other choice but keeping track of your listeners. I went ahead and made this quickly, it should fix your problem.
var listeners = {};
function createDiv() {
var outerFrame = document.createElement('div');
outerFrame.className = 'popup-outer';
return outerFrame;
}
function displayImage() {
var div = createDiv();
bindEvent(div);
document.body.appendChild(div);
}
function bindEvent(el) {
var handler = function(e) {
hideImg.call(el, e);
}
listeners[el] = handler;
document.body.addEventListener('keyup', handler, false);
}
function hideImg(e) {
if (e.keyCode === 27) {
// listeners[this] refers to the "private" handler variable we created in the bindEvent function
document.body.removeEventListener('keyup', listeners[this], false);
delete listeners[this];
document.body.removeChild(this);
}
}

html5 audio bind timeupdate before element exists

im trying to bind the "timeupdate" event from an audio tag, which doesn't exist yet. I was used to do it this way:
$("body").on("click","#selector", function(e) {
});
I tried this with the audio tag:
$("body").on("timeupdate", ".audioPlayerJS audio", function(e) {
alert("test");
console.log($(".audioPlayerJS audio").prop("currentTime"));
$(".audioPlayerJS span.current-time").html($(".audioPlayerJS audio").prop("currentTime"));
});
This doesn't work though. Is this supposed to work? Or what am I doing wrong?
Any help is highly appreciated.
There is a fiddel for you: jsfiddel
Apparently media events( those specifically belonging to audio or video like play, pause, timeupdate, etc) do not get bubbled. you can find the explanation for that in the answer to this question.
So using their solution, I captured the timeupdate event,
$.createEventCapturing(['timeupdate']);
$('body').on('timeupdate', '.audioPlayerJS audio', updateTime); // now this would work.
JSFiddle demo
the code for event capturing( taken from the other SO answer):
$.createEventCapturing = (function () {
var special = $.event.special;
return function (names) {
if (!document.addEventListener) {
return;
}
if (typeof names == 'string') {
names = [names];
}
$.each(names, function (i, name) {
var handler = function (e) {
e = $.event.fix(e);
return $.event.dispatch.call(this, e);
};
special[name] = special[name] || {};
if (special[name].setup || special[name].teardown) {
return;
}
$.extend(special[name], {
setup: function () {
this.addEventListener(name, handler, true);
},
teardown: function () {
this.removeEventListener(name, handler, true);
}
});
});
};
})();

Can multiple event listeners/handlers be added to the same element using Javascript?

I have:
if (window.addEventListener) {
window.addEventListener('load',videoPlayer,false);
}
else if (window.attachEvent) {
window.attachEvent('onload',videoPlayer);
}
and then later I have:
if (window.addEventListener) {
window.addEventListener('load',somethingelse,false);
} else if (window.attachEvent) {
window.attachEvent('onload',somethingelse);
}
Is it preferred/functional to have them all together? Like
if (window.addEventListener) {
window.addEventListener('load',videoPlayer,false);
window.addEventListener('load',somethingelse,false);
} else if (window.attachEvent) {
window.attachEvent('onload',videoPlayer,false);
window.attachEvent('onload',somethingelse);
}
You can do how ever you want it to do. They don't have to be together, it depends on the context of the code. Of course, if you can put them together, then you should, as this probably makes the structure of your code more clear (in the sense of "now we are adding all the event handlers").
But sometimes you have to add event listeners dynamically. However, it is unnecessary to test multiple times whether you are dealing with IE or not.
Better would be to abstract from this and test only once which method is available when the page is loaded. Something like this:
var addEventListener = (function() {
if(document.addEventListener) {
return function(element, event, handler) {
element.addEventListener(event, handler, false);
};
}
else {
return function(element, event, handler) {
element.attachEvent('on' + event, handler);
};
}
}());
This will test once which method to use. Then you can attach events throughout your script with:
addEventListener(window, 'load',videoPlayer);
addEventListener(window, 'load',somethingelse);
I use this function:
function addEvent (obj, type, fn) {
if (obj.addEventListener) {
obj.addEventListener(type, fn, false);
} else if (obj.attachEvent) {
obj.attachEvent('on' + type, function () {
return fn.call(obj, window.event);
});
}
}
/**
* multipleEventsListeners.js
* Add the capability to attach multiple events to an element, just like jQuery does
* https://gist.github.com/juanbrujo/a1f77db1e6f7cb17b42b
*/
multipleEventsListeners(events, func, elem) {
elem = elem || document;
var event = events.split(' ');
for (var i = 0; i < event.length; i++) {
elem.addEventListener(event[i], func, false);
}
}
/*
Use:
var input = document.querySelector('input');
multipleEventsListeners(input, 'keyup change', function(e){
console.log = this.value;
});
*/
from: https://gist.github.com/juanbrujo/a1f77db1e6f7cb17b42b
by using a named function and passing that into your event listener, you can avoid having to write the same code over and over again.
// Setup our function to run on various events
var someFunction = function (event) {
// Do something...
};
// Add our event listeners
window.addEventListener('click', someFunction, false);
window.addEventListener('mouseover', someFunction, false);
addEventListener automatically passes the event object into your function as an

Categories

Resources