What is event bubbling

Event bubbling is an event propagation mechanism in JavaScript. When an event is triggered on an element, the event will be processed on the element, and over time, it will be passed to Its parent element is passed all the way to the root element of the document. This propagation process is called event bubbling. The process of event bubbling is similar to the process of water bubbles rising from the bottom to the surface. The event is triggered first on the deepest element and then propagates upward until it reaches the outermost parent element.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

Event bubbling is an event propagation mechanism in JavaScript. When an event is triggered on an element, the event is handled on that element and passed down the hierarchy to its parent elements over time, all the way to the root element of the document (i.e. the `window` object ). This propagation process is called event bubbling.

The process of event bubbling is similar to the process of water bubbles rising from the bottom to the surface. The event is triggered first on the deepest element and then propagates upward until it reaches the outermost parent element.

For example, consider the following HTML code:

<div id="parent">
  <div id="child">
    <button id="button">Click me</button>
  </div>
</div>

Suppose we add a click event listener to the `button` button as follows:

document.getElementById("button").addEventListener("click", function() {
  console.log("Button clicked!");
});

When clicked `button` button, the event is first triggered on the button and then starts to propagate upward. In this case, the event is passed to the `child` element, then to the `parent` element, and finally to the `window` object. So in the browser's console, we will see "Button clicked!" printed out.

The advantage of the event bubbling mechanism is that it allows simpler and more flexible event handling. By placing event handlers on the parent element, you can handle similar events for multiple child elements without changing the child element's code. This avoids the tedious task of setting up event handlers for each child element.

In addition, event bubbling also allows deeper elements to intercept the event and prevent it from continuing to bubble. By calling the `event.stopPropagation()` method in the event handler, you can prevent the event from continuing to propagate upward. This is useful for specific elements that must be processed individually.

However, sometimes event bubbling can lead to unexpected results or unwanted behavior. In some cases, we may want to prevent an event from bubbling to ensure that the event is only handled on a specific element. This can be achieved by calling the `event.stopPropagation()` method or `event.cancelBubble = true` (in older versions of IE). Doing this prevents events from propagating to the parent element.

In summary, event bubbling is an event propagation mechanism in JavaScript that allows events to propagate from child elements to parent elements until they are propagated to the outermost parent element or the root element of the document. It provides a simple and flexible way of handling events, but sometimes requires care to avoid unexpected behavior.

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