I'm trying to remove an event listener inside of a listener definition:
canvas.addEventListener('click', function(event) {
click++;
if(click == 50) {
// remove this event listener here!
}
// More code here ...
How could I do that? this = event... Thank you.
This question is related to
javascript
events
event-handling
listener
If someone uses jquery, he can do it like this :
var click_count = 0;
$( "canvas" ).bind( "click", function( event ) {
//do whatever you want
click_count++;
if ( click_count == 50 ) {
//remove the event
$( this ).unbind( event );
}
});
Hope that it can help someone. Note that the answer given by @user113716 work nicely :)
I think you may need to define the handler function ahead of time, like so:
var myHandler = function(event) {
click++;
if(click == 50) {
this.removeEventListener('click', myHandler);
}
}
canvas.addEventListener('click', myHandler);
This will allow you to remove the handler by name from within itself.
If @Cybernate's solution doesn't work, try breaking the trigger off in to it's own function so you can reference it.
clickHandler = function(event){
if (click++ == 49)
canvas.removeEventListener('click',clickHandler);
}
canvas.addEventListener('click',clickHandler);
You could use a named function expression (in this case the function is named abc
), like so:
let click = 0;
canvas.addEventListener('click', function abc(event) {
click++;
if (click >= 50) {
// remove event listener function `abc`
canvas.removeEventListener('click', abc);
}
// More code here ...
}
Quick and dirty working example: http://jsfiddle.net/8qvdmLz5/2/.
More information about named function expressions: http://kangax.github.io/nfe/.
canvas.addEventListener('click', function(event) {
click++;
if(click == 50) {
this.removeEventListener('click',arguments.callee,false);
}
Should do it.
You need to use named functions.
Also, the click
variable needs to be outside the handler to increment.
var click_count = 0;
function myClick(event) {
click_count++;
if(click_count == 50) {
// to remove
canvas.removeEventListener('click', myClick);
}
}
// to add
canvas.addEventListener('click', myClick);
EDIT: You could close around the click_counter
variable like this:
var myClick = (function( click_count ) {
var handler = function(event) {
click_count++;
if(click_count == 50) {
// to remove
canvas.removeEventListener('click', handler);
}
};
return handler;
})( 0 );
// to add
canvas.addEventListener('click', myClick);
This way you can increment the counter across several elements.
If you don't want that, and want each one to have its own counter, then do this:
var myClick = function( click_count ) {
var handler = function(event) {
click_count++;
if(click_count == 50) {
// to remove
canvas.removeEventListener('click', handler);
}
};
return handler;
};
// to add
canvas.addEventListener('click', myClick( 0 ));
EDIT: I had forgotten to name the handler being returned in the last two versions. Fixed.
Try this, it worked for me.
<button id="btn">Click</button>
<script>
console.log(btn)
let f;
btn.addEventListener('click', f=function(event) {
console.log('Click')
console.log(f)
this.removeEventListener('click',f)
console.log('Event removed')
})
</script>
element.querySelector('.addDoor').onEvent('click', function (e) { });
element.querySelector('.addDoor').removeListeners();
HTMLElement.prototype.onEvent = function (eventType, callBack, useCapture) {
this.addEventListener(eventType, callBack, useCapture);
if (!this.myListeners) {
this.myListeners = [];
};
this.myListeners.push({ eType: eventType, callBack: callBack });
return this;
};
HTMLElement.prototype.removeListeners = function () {
if (this.myListeners) {
for (var i = 0; i < this.myListeners.length; i++) {
this.removeEventListener(this.myListeners[i].eType, this.myListeners[i].callBack);
};
delete this.myListeners;
};
};
Source: Stackoverflow.com