prevent-listener

The prevent-listener snippet prevents the addition of event listeners.

You can use prevent-listener by wrapping EventTarget.prototype.addEventListener and not allowing listeners to be added for certain event types.

Parameters

Name	Description	Mandatory
type	A pattern that matches the type(s) of events you want to prevent. If the string starts and ends with a slash (/), the text in between is treated as a regular expression.	Yes
handler	A pattern that matches the event handler's declaration. If the string starts and ends with a slash (/), the text in between is treated as a regular expression.	No
selector	The CSS selector that the event target must match. If the event target is not an HTML element, the event handler is added.	No

Filter examples

The following table lists examples that use the abort-on-iframe-property-write snippet:

Filter	Result
prevent-listener click	No event listener will be added for click events.
prevent-listener click console div	No click event listener will be added on div elements whose handler matches console. For example, these listeners won't be added: window.addEventListener("click", ()=>console.log("click")) document.body.addEventListener("click", ()=>console.log("click")) But this listener would be added: omeDiv.addEventListener("click", ()=>console.log("click"))
prevent-listener click console	No listener will be added for click events whose handler matches console. For example, these listeners won't be added: someElement.addEventListener("click", () => console.log("click")) But these listeners would be added: someElement.addEventListener("click", () => alert("click"))

Debugging

The following table contains messages you'll find useful during debugging:

Message	When the message occurs	Definition
DEBUG [prevent] Wrapped addEventListener	After wrapping	Displayed after addEventListener has been wrapped.
DEBUG [prevent] was successful DEBUG [prevent] type: actualType matching providedType DEBUG [prevent]handler: actualHandler DEBUG [prevent] matching providedHandler DEBUG [prevent] on element actualElement matching selector DEBUG [prevent] was prevented from being added	Each time a listener is prevented from being added	This is a group of logs containing detailed information about the event type and its handler. They're displayed each time we prevent a listener from being added. If the optional handler or selector parameter was omitted, the corresponding log(s) will be skipped.