How to prevent a tag from jumping in javascript

In Web development, the a tag is a very common tag. It is used to define a link. When the user clicks the link, the browser will jump to the address specified by the link. But in some cases, we don't need to jump to a new page. For example, in a single-page application, we just want to update the page content through JavaScript. At this time, we can use some attributes of the a tag to prevent its default behavior and implement customized operations.

1. Prevent the a tag from jumping

In the a tag, you can use JavaScript's void(0) expression as the value of the href attribute to prevent the default behavior of the a tag. For example:

<a href="javascript:void(0)">点击这里</a>

When the user clicks this link, the browser will not jump. However, it should be noted that although this method can prevent the default behavior, it will not prevent the delivery of events. That is to say, after clicking this link, the click event will still be passed to the parent element. If you want to prevent the event from being delivered, you need to Add event.stopPropagation() code to the event handling function, for example:

<div id="parent">
  <a href="javascript:void(0)" onClick="event.stopPropagation()">点击这里</a>
</div>

When the user clicks on this link, not only will no jump occur, but the event will not be passed to the parent element.

2. Customize click events

In the a tag, in addition to using void(0) to prevent the default behavior, you can also use JavaScript code to customize the click event. For example:

<a href="#" onClick="alert(&#39;这是一个自定义点击事件&#39;)">点击这里</a>

The href attribute value here is '#'. When the user clicks on this link, although it will jump to the top of the current page (because '#' represents an anchor point in the page), but Due to the alert statement in the onClick event handling function, a prompt box will be displayed to tell the user that this is a custom click event.

The advantage of this method is that you can operate JavaScript code in the click event without blocking the delivery of the event or preventing the default behavior, because this method will first execute the event processing function, and then Perform default behavior. But the disadvantage is that if you need to define multiple custom click events, the code will become bloated. And this method cannot prevent multiple click events from being triggered.

3. Use event listeners

In order to solve the above problems, you can use the JavaScript event listener addEventListener() method to bind custom events to the a tag. For example:

<a href="#" id="myLink">点击这里</a>

document.querySelector('#myLink').addEventListener('click', function() {
  alert('这是一个自定义点击事件');
});

This method can decouple custom events from the a tag, while preventing default behavior and event delivery. And this method can also solve the problem of multiple click event triggers, because each click will only execute a custom event once. In addition, event listeners can also be used to pass parameters for custom events to achieve more flexible operations.

4. Summary

In Web development, the a tag is a very common tag, but in some cases, we do not need its default behavior, or we want to add more information to the click event. Multiple JavaScript codes. At this time, we can use some attributes of the a tag and JavaScript code to define our own operations. However, it should be noted that these methods must consider how to prevent default behavior and event delivery, and how to solve the problem of triggering multiple click events. When using the above methods, you need to choose the method that best suits you according to the actual situation.

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