如何检查JavaScript-Eventhandler是否已设置？ [英] How can i check if a JavaScript-Eventhandler has been set?

问题描述

我有一个JavaScript函数设置onclick - 一些HTML节点的事件 - 即使之前已经设置了onclick-event。

I've got a JavaScript-function that sets the "onclick"-event of some HTML-Nodes - even if that "onclick"-event has been set before.

我如何检查该事件是否已经设置好了，所以我可以扩展我的功能，仅在尚未设置的HTML节点上设置事件？

How can i check if that event has already been set, so I can extend my function to set the event only on HTML-Nodes where it has not already been set?

推荐答案

检查，如下所示：

if(typeof someNode.onclick == "function") {
   // someNode has an event handler already set for the onclick event...
}

顺便说一下，如果您使用的是图书馆，您应该这么说 - 如果是，可能会更容易/更清洁，会有所不同根据您正在使用的图书馆...

By the way, if you are using a library, you should say so - if you are, it might be easier/cleaner and would differ based on which library you are using...

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