What problems can js event bubbling solve?

Problems that js event bubbling can solve: 1. Simplify event processing logic; 2. Improve event processing performance; 3. Implement custom components and interactive effects; 4. Control event propagation direction; 5. Solve events Coverage issues; 6. Implement global event monitoring; 7. Convenient debugging and troubleshooting. Detailed introduction: 1. Simplify event processing logic. In complex web applications, event processing often needs to be performed on a large number of elements. If event processing functions are bound to each element separately, the code will become redundant and difficult to maintain; 2. Improve event processing performance, etc.

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

The event bubbling mechanism in JavaScript can solve the following problems:

1. Simplify event processing logic

In complex web applications, It is often necessary to handle events on a large number of elements. If you bind event handlers to each element individually, the code will become redundant and difficult to maintain. Through event bubbling, the event listener can be bound to the parent element, and the parent element can uniformly handle the events of the child elements, thus simplifying the event processing logic. This approach is called event delegation.

2. Improve event processing performance

When there are a large number of elements in the page that need to be bound to event processing functions, if you bind each element directly, it will consume A large amount of memory and computing resources, resulting in reduced page performance. Through event bubbling, event listeners can be bound to parent elements, reducing the number of event listeners, reducing memory consumption and computing burden, thereby improving event processing performance.

3. Implement custom components and interactive effects

In web development, it is often necessary to implement custom components and interactive effects, such as modal boxes, drop-down menus, Carousel images, etc. These components usually need to handle user clicks, slides and other operations. Through event bubbling, these operations can be easily delegated to the parent element or ancestor element of the component for processing, thereby achieving the interactive effect of the component.

4. Control the propagation direction of events

In some cases, it is necessary to accurately control the propagation direction of events. For example, when a button is clicked, you may only want the button's event handler to be triggered, but not the event to continue bubbling up to trigger the event handlers of other elements. By calling the event.stopPropagation() method, you can prevent the event from bubbling upward, thereby controlling the propagation direction of the event.

5. Solving the event coverage problem

On the same element, multiple event handling functions may be bound. If these functions all attempt to modify the properties or state of the same element, the results of other functions may be overwritten. By performing event processing during the event bubbling phase, you can ensure that each function is executed independently and does not overwrite each other.

6. Implement global event monitoring

Sometimes, it is necessary to monitor an event within the entire page, such as keyboard keys, window size adjustment, etc. Global event monitoring can be easily implemented by binding event listeners to document or window objects and using the event bubbling mechanism. This method is often used to implement global shortcut keys, responsive layout and other functions.

7. Convenient debugging and troubleshooting

By binding an event listener on the parent element and outputting relevant information in the event processing function, debugging can be facilitated and troubleshoot event handling issues on child elements. This method is often used to locate and solve event-related problems during the development process.

It should be noted that although the event bubbling mechanism can solve the above problems, overuse or incorrect use may cause performance problems or unexpected behavior. Therefore, when using the event bubbling mechanism, you need to carefully consider its applicable scenarios and potential risks.

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