How does javascript uncheck the event

This article will explain in detail how to cancel the selection of javascript. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Javascript uncheck the event: you can uncheck the event by deleting the event handler, for example, [btn.onclick = null;].

This article operating environment: windows10 system, javascript 1.8.5, thinkpad T480 computer.

Event handlers are divided into DOM0 level and DOM2 level. If the event is bound by onclick, you can cancel it in the following ways:

Btn.onclick=null;// delete event handler

If you add an event using the addEventListener () method, you can remove the event through removeEventListener (). There are two things to note:

1. The third parameter of removeEventListener () must be the same as the third parameter of the addEventListener () method.

2. Anonymous functions added through the addEventListener () method cannot be removed.

Btn.aaddEventListener ('click',function () {alert (1);}, false); btn.removeEventListener (' click',function () {alert (1);}, false); / / useless!

AaddEventListener and removeEventListener seem to pass in the same parameter, but in fact the second parameter of removeEventListener is a completely different function from the second parameter of aaddEventListener!

You have to do this if you want to move out.

Var fn=function () {alert (1);}; btn.aaddEventListener ('click',fn,false); btn.removeEventListener (' click',fn,false); / / this is the end of the article on "how to uncheck the event of javascript". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.