What are the instructions to prevent bubbling events?

Instructions to prevent bubbling events: 1. stopPropagation(); 2. e.stopPropagation(); 3. return false; 4. Use the capture option in the parameters of addEventListener(). Detailed introduction: 1. stopPropagation() is a method in JavaScript that is used to prevent the bubbling delivery of events. When the event is triggered, the stopPropagation() method is called, etc.

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

Bubbling events mean that in front-end development, when an element triggers an event, the event will be passed to the parent element until it reaches the top-level parent element or is prevented from bubbling. The instructions to prevent bubbling events are as follows:

1. stopPropagation(): stopPropagation() is a method in JavaScript that is used to prevent the bubbling delivery of events. When the event is triggered, calling the stopPropagation() method will prevent the event from continuing to be passed to the parent element. For example, you can use this method on a button click event to prevent the event from bubbling up, ensuring that only the button itself triggers the event.

2. e.stopPropagation(): e is an event object, representing the currently triggered event. By calling the stopPropagation() method of the event object, you can prevent the event from bubbling. For example, in an event handler for clicking a link, you can use e.stopPropagation() to prevent the event from bubbling, ensuring that only the link itself triggers the event, and not the event of the parent element where the link is located.

3. return false: In some specific cases, you can prevent the event from bubbling by returning false in the event handling function. When the event handling function returns false, the browser will automatically call e.stopPropagation() and e.preventDefault() to prevent the event from bubbling and default behavior. For example, in a form's submit event handler, you can use return false to prevent the event from bubbling and prevent the form from being submitted.

4. Use the capture option in the parameters of addEventListener(): addEventListener() is the method used to add event listeners in JavaScript. The third parameter of this method is a Boolean value indicating whether to use event capture. When this parameter is set to true, events will be delivered using event capture mode, starting from the top-most parent element and proceeding to the target element. In event capture mode, you can stop the event from bubbling by calling stopPropagation() in the event handler function. For example, you can use addEventListener('click', handler, true) to prevent the event from bubbling during the event capture phase.

To summarize, the instructions to prevent bubbling events mainly include stopPropagation(), e.stopPropagation(), return false and use the capture option. Developers can choose appropriate instructions based on specific needs to prevent bubbling events and ensure that events are only triggered on the target element.

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