Master effective techniques to prevent events from bubbling up

Mastering effective techniques for preventing event bubbling requires specific code examples

With the continuous development of the Internet, Web development has become more and more important. During the development process, we often encounter situations where event bubbling is handled. The so-called event bubbling means that when an element triggers an event, the event will be propagated to the upper element until it is propagated to the root element of the entire DOM tree. This bubbling behavior may sometimes cause problems in our event processing logic, affecting the functionality and interactive effects of the web page. Therefore, it is very important for developers to master the skills of preventing events from bubbling up.

In this article, I will introduce some effective techniques for preventing event bubbling and provide specific code examples.

1. stopPropagation method

The stopPropagation method is a method provided in JavaScript to stop the propagation of event bubbling. Use this method to prevent events from propagating to parent elements.

Sample code:

document.getElementById("innerDiv").addEventListener("click", function(event){
  alert("内部元素被点击");
  event.stopPropagation();
});

document.getElementById("outerDiv").addEventListener("click", function(){
  alert("外部元素被点击");
});

In the above code, when the "innerDiv" element is clicked, only the "inner element was clicked" prompt box will pop up, and will not trigger the click of the external element. event. This is because we called the event.stopPropagation() method in the event handler of the inner element to prevent the event from bubbling.

2. event.preventDefault method

The event.preventDefault method is used to prevent the browser from performing the default action of the event. Sometimes the default action for an event can cause the event to bubble up. Therefore, the purpose of preventing event bubbling is achieved by blocking the default action.

Sample code:

document.getElementById("innerLink").addEventListener("click", function(event){
  event.preventDefault();
  alert("内部链接被点击");
});

document.getElementById("innerSpan").addEventListener("click", function(){
  alert("内部span被点击");
});

document.getElementById("outerDiv").addEventListener("click", function(){
  alert("外部元素被点击");
});

In the above code, when the "innerLink" link is clicked, the browser's default jump behavior will not be triggered, and only the "inner link clicked" popup will appear. " prompt box. At this time, even if the parent element "outerDiv" of "innerLink" is clicked, the click event of the external element will not be triggered.

3. Use e.stopPropagation and e.stopImmediatePropagation methods

In some cases, we may need to use both e.stopPropagation and e.stopImmediatePropagation in the event handler function Method to completely prevent the propagation of event bubbling, even the event handler function of the subordinate element will not be executed.

Sample code:

document.getElementById("innerDiv").addEventListener("click", function(event){
  event.stopImmediatePropagation();
  alert("内部元素被点击");
});

document.getElementById("innerDiv").addEventListener("click", function(){
  alert("内部元素的另一个点击事件处理函数");
});

document.getElementById("outerDiv").addEventListener("click", function(){
  alert("外部元素被点击");
});

In the above code, when the "innerDiv" element is clicked, only the "inner element was clicked" prompt box will pop up, and the inner element will not be triggered. Another click event handler function.

Summary:

In web development, preventing events from bubbling is very important to handle events correctly. This article introduces three effective techniques for preventing event bubbling: using the stopPropagation method, using the preventDefault method, and using the stopPropagation and stopImmediatePropagation methods. By flexibly using these techniques, we can better control the propagation of events and improve the interactive effect and user experience of web pages.

The above is the introduction and specific code examples of this article’s techniques for preventing event bubbling. I hope readers can flexibly use these techniques in actual development to better deal with event bubbling problems.

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