实现 jQuery 的“live"带有本机 Javascript 的活页

问题描述

我试图弄清楚如何将事件绑定到动态创建的元素.即使在元素被销毁和重新生成后，我也需要该事件在元素上持续存在.

I am trying to figure out how to bind an event to dynamically created elements. I need the event to persist on the element even after it is destroyed and regenerated.

显然使用 jQuery 的 live 函数很容易，但是使用原生 Javascript 实现它们会是什么样子?

Obviously with jQuery's live function its easy, but what would they look like implemented with native Javascript?

推荐答案

这是一个简单的例子:

function live(eventType, elementId, cb) {
    document.addEventListener(eventType, function (event) {
        if (event.target.id === elementId) {
            cb.call(event.target, event);
        }
    });
}

live("click", "test", function (event) {
    alert(this.id);
});

基本思想是您希望将事件处理程序附加到文档并让事件在 DOM 中冒泡.然后，检查 event.target 属性以查看它是否符合所需条件(在本例中，就是元素的 id).

The basic idea is that you want to attach an event handler to the document and let the event bubble up the DOM. Then, check the event.target property to see if it matches the desired criteria (in this case, just that the id of the element).

@shabunc 发现了一个很大的问题使用我的解决方案 - 无法正确检测到子元素上的事件.解决此问题的一种方法是查看祖先元素以查看是否有指定的 id:

@shabunc discovered a pretty big problem with my solution-- events on child elements won't be detected correctly. One way to fix this is to look at ancestor elements to see if any have the specified id:

function live (eventType, elementId, cb) {
    document.addEventListener(eventType, function (event) {
        var el = event.target
            , found;

        while (el && !(found = el.id === elementId)) {
            el = el.parentElement;
        }

        if (found) {
            cb.call(el, event);
        }
    });
}

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