EventTarget: removeEventListener() method
Note: This feature is available in Web Workers.
The removeEventListener()
method of the EventTarget
interface
removes an event listener previously registered with EventTarget.addEventListener()
from the target.
The event listener to be removed is identified using a combination of the event type,
the event listener function itself, and various optional options that may affect the matching process;
see Matching event listeners for removal.
Calling removeEventListener()
with arguments that do not identify any
currently registered event listener on the EventTarget
has no
effect.
If an event listener is removed from an EventTarget
while another listener of the target is processing an event, it will not be triggered by the event. However, it can be reattached.
Warning: If a listener is registered twice, one with the capture flag set and one without, you must remove each one separately. Removal of a capturing listener does not affect a non-capturing version of the same listener, and vice versa.
Event listeners can also be removed by passing an AbortSignal
to an addEventListener()
and then later calling abort()
on the controller owning the signal.
Syntax
removeEventListener(type, listener)
removeEventListener(type, listener, options)
removeEventListener(type, listener, useCapture)
Parameters
type
-
A string which specifies the type of event for which to remove an event listener.
listener
-
The event listener function of the event handler to remove from the event target.
options
Optional-
An options object that specifies characteristics about the event listener.
The available options are:
capture
: A boolean value that specifies whether the event listener to be removed is registered as a capturing listener or not. If this parameter is absent, the default valuefalse
is assumed.
useCapture
Optional-
A boolean value that specifies whether the event listener to be removed is registered as a capturing listener or not. If this parameter is absent, the default value
false
is assumed.
Return value
None.
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()
.
Example
This example shows how to add a mouseover
-based event listener that
removes a click
-based event listener.
const body = document.querySelector("body");
const clickTarget = document.getElementById("click-target");
const mouseOverTarget = document.getElementById("mouse-over-target");
let toggle = false;
function makeBackgroundYellow() {
body.style.backgroundColor = toggle ? "white" : "yellow";
toggle = !toggle;
}
clickTarget.addEventListener("click", makeBackgroundYellow, false);
mouseOverTarget.addEventListener("mouseover", () => {
clickTarget.removeEventListener("click", makeBackgroundYellow, false);
});
Specifications
Specification |
---|
DOM Standard # ref-for-dom-eventtarget-removeeventlistener② |
Browser compatibility
BCD tables only load in the browser