EventTarget.removeEventListener()
메서드는 이전에EventTarget.addEventListener()
로 EventTarget
에 등록했던 이벤트 리스너를 제거합니다. 이 이벤트 리스너는 이벤트 종류와 이벤트 리스너 함수 자체의 조합으로 식별되어 제거되며, 등록시 제공했던 다양한 옵션과 일치하는 이벤트 리스너만 제거할 수 있습니다. Matching event listeners for removal를 참고하세요.
Syntax
target.removeEventListener(type, listener[, options]);
target.removeEventListener(type, listener[, useCapture]);
Parameters
type
- 제거할 이벤트 리스너의 이벤트 타입을 지정합니다.
listener
- 이벤트 타깃에서 제거할 이벤트 핸들러 함수,
EventListener
를 지정합니다. options
Optional- 이벤트 리스너에 대한 특징, 즉 제거할 이벤트 리스너의 옵션들을 지정합니다. 지정할 수 있는 옵션들은 아래와 같습니다.
useCapture
Optional- Specifies whether the
EventListener
to be removed is registered as a capturing listener or not. If this parameter is absent, a default value offalse
is assumed. - If a listener is registered twice, one with capture and one without, remove each one separately. Removal of a capturing listener does not affect a non-capturing version of the same listener, and vice versa.
Return value
undefined
.
Matching event listeners for removal
Given an event listener previously added by calling addEventListener()
, you may eventually come to a point at which you need to remove it. Obviously, you need to specify the same type
and listener
parameters to removeEventListener()
, but what about the options
or useCapture
parameters?
While addEventListener()
will let you add the same listener more than once for the same type if the options are different, the only option removeEventListener()
checks is the capture
/useCapture
flag. Its value must match for removeEventListener()
to match, but the other values don't.
For example, consider this call to addEventListener()
:
element.addEventListener("mousedown", handleMouseDown, true);
Now consider each of these two calls to removeEventListener()
:
element.removeEventListener("mousedown", handleMouseDown, false); // Fails
element.removeEventListener("mousedown", handleMouseDown, true); // Succeeds
The first call fails because the value of useCapture
doesn't match. The second succeeds, since useCapture
matches up.
Now consider this:
element.addEventListener("mousedown", handleMouseDown, { passive: true });
Here, we specify an options
object in which passive
is set to true
, while the other options are left to the default value of false
.
Now look at each of these calls to removeEventListener()
in turn. Any of them in which capture
or useCapture
is true
fail; all others succeed. Only the capture
setting matters to removeEventListener()
.
element.removeEventListener("mousedown", handleMouseDown, { passive: true }); // Succeeds
element.removeEventListener("mousedown", handleMouseDown, { capture: false }); // Succeeds
element.removeEventListener("mousedown", handleMouseDown, { capture: true }); // Fails
element.removeEventListener("mousedown", handleMouseDown, { passive: false }); // Succeeds
element.removeEventListener("mousedown", handleMouseDown, false); // Succeeds
element.removeEventListener("mousedown", handleMouseDown, true); // Fails
It's worth noting that some browser releases have been inconsistent on this, and unless you have specific reasons otherwise, it's probably wise to use the same values used for the call to addEventListener()
when calling removeEventListener()
.
Notes
If an EventListener
is removed from an EventTarget
while it is processing an event, it will not be triggered by the current actions. An EventListener
will not be invoked for the event it was registered for after being removed. However, it can be reattached.
Calling removeEventListener()
with arguments that do not identify any currently registered EventListener
on the EventTarget
has no effect.
Example
This example shows how to add a click
-based event listener and remove a mouseover
-based event listener.
var body = document.querySelector('body'),
clickTarget = document.getElementById('click-target'),
mouseOverTarget = document.getElementById('mouse-over-target'),
toggle = false;
function makeBackgroundYellow() {
'use strict';
if (toggle) {
body.style.backgroundColor = 'white';
} else {
body.style.backgroundColor = 'yellow';
}
toggle = !toggle;
}
clickTarget.addEventListener('click',
makeBackgroundYellow,
false
);
mouseOverTarget.addEventListener('mouseover', function () {
'use strict';
clickTarget.removeEventListener('click',
makeBackgroundYellow,
false
);
});
Specifications
Specification | Status | Comment |
---|---|---|
DOM The definition of 'EventTarget.removeEventListener()' in that specification. |
Living Standard | |
DOM4 The definition of 'EventTarget.removeEventListener()' in that specification. |
Obsolete | |
Document Object Model (DOM) Level 2 Events Specification The definition of 'EventTarget.removeEventListener()' in that specification. |
Obsolete | Initial definition |
Browser compatibility
BCD tables only load in the browser
Polyfill to support older browsers
addEventListener()
and removeEventListener()
are not present in older browsers. You can work around this by inserting the following code at the beginning of your scripts, allowing the use of addEventListener()
and removeEventListener()
in implementations that do not natively support it. However, this method will not work on Internet Explorer 7 or earlier, since extending the Element.prototype was not supported until Internet Explorer 8.
if (!Element.prototype.addEventListener) {
var oListeners = {};
function runListeners(oEvent) {
if (!oEvent) { oEvent = window.event; }
for (var iLstId = 0, iElId = 0, oEvtListeners = oListeners[oEvent.type]; iElId < oEvtListeners.aEls.length; iElId++) {
if (oEvtListeners.aEls[iElId] === this) {
for (iLstId; iLstId < oEvtListeners.aEvts[iElId].length; iLstId++) { oEvtListeners.aEvts[iElId][iLstId].call(this, oEvent); }
break;
}
}
}
Element.prototype.addEventListener = function (sEventType, fListener /*, useCapture (will be ignored!) */) {
if (oListeners.hasOwnProperty(sEventType)) {
var oEvtListeners = oListeners[sEventType];
for (var nElIdx = -1, iElId = 0; iElId < oEvtListeners.aEls.length; iElId++) {
if (oEvtListeners.aEls[iElId] === this) { nElIdx = iElId; break; }
}
if (nElIdx === -1) {
oEvtListeners.aEls.push(this);
oEvtListeners.aEvts.push([fListener]);
this["on" + sEventType] = runListeners;
} else {
var aElListeners = oEvtListeners.aEvts[nElIdx];
if (this["on" + sEventType] !== runListeners) {
aElListeners.splice(0);
this["on" + sEventType] = runListeners;
}
for (var iLstId = 0; iLstId < aElListeners.length; iLstId++) {
if (aElListeners[iLstId] === fListener) { return; }
}
aElListeners.push(fListener);
}
} else {
oListeners[sEventType] = { aEls: [this], aEvts: [ [fListener] ] };
this["on" + sEventType] = runListeners;
}
};
Element.prototype.removeEventListener = function (sEventType, fListener /*, useCapture (will be ignored!) */) {
if (!oListeners.hasOwnProperty(sEventType)) { return; }
var oEvtListeners = oListeners[sEventType];
for (var nElIdx = -1, iElId = 0; iElId < oEvtListeners.aEls.length; iElId++) {
if (oEvtListeners.aEls[iElId] === this) { nElIdx = iElId; break; }
}
if (nElIdx === -1) { return; }
for (var iLstId = 0, aElListeners = oEvtListeners.aEvts[nElIdx]; iLstId < aElListeners.length; iLstId++) {
if (aElListeners[iLstId] === fListener) { aElListeners.splice(iLstId, 1); }
}
};
}