Optimizing page interaction experience: practical tips for event bubbling and event capturing-JS Tutorial-php.cn

Optimizing page interaction experience: practical tips for event bubbling and event capturing

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Release： 2024-01-13 11:35:05

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Optimizing page interaction experience: practical tips for event bubbling and event capturing

How to use event bubbling and event capturing to optimize page interaction experience

In web development, event bubbling and event capturing are two common event propagation mechanisms. They allow us to better handle interactive behaviors on the page and improve user experience. This article will introduce how to use event bubbling and event capturing to optimize page interaction, and give specific code examples.

1. Event bubbling

Event bubbling means that when an event (such as a click event) occurs on an element, this event will propagate to the upper element until it is propagated to the document object. . Through event bubbling, we can easily delegate events to multiple elements, simplify code writing and processing, and improve performance.

The following is a sample code for event bubbling:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>事件冒泡示例</title>
</head>
<body>
    <div id="container">
        <button id="btn1">按钮1</button>
        <button id="btn2">按钮2</button>
        <button id="btn3">按钮3</button>
    </div>

    <script>
        document.getElementById('container').addEventListener('click', function(event) {
            if(event.target.tagName === 'BUTTON') {
                console.log('点击了按钮：' + event.target.innerText);
            }
        });
    </script>
</body>
</html>

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In the above code, we add the container element <div id="container"> A click event listener is created. When any button in the container is clicked, the event will bubble up to the container element and execute the code in the listener. By determining whether the target element of the event is a button, we can handle the button click event accordingly without adding a listener to each button, which greatly simplifies the code.

2. Event Capture

Event capture is the opposite of event bubbling. It starts from the document object and propagates to the specific target element. Through event capture, we can perform some special processing on the event before it reaches the target element, thereby better controlling the interactive effects and feedback of the event.

The following is a sample code for event capture:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>事件捕获示例</title>
</head>
<body>
    <div id="container">
        <button id="btn1">按钮1</button>
        <button id="btn2">按钮2</button>
        <button id="btn3">按钮3</button>
    </div>

    <script>
        document.getElementById('container').addEventListener('click', function(event) {
            if(event.target.tagName === 'BUTTON') {
                event.stopPropagation();   // 阻止事件冒泡
                console.log('点击了按钮：' + event.target.innerText);
            }
        }, true);
    </script>
</body>
</html>

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In the above code, we added the container element <div id="container"> A click event listener, and set the event listener parameter useCapture to true to enable event capture. When any button in the container is clicked, the event will first be propagated to the container element and the code in the listener will be executed. By event.stopPropagation() to prevent event bubbling, we can only process the click event of the target element without affecting the event propagation of other elements.

Conclusion


By making reasonable use of event bubbling and event capturing, we can optimize the page interaction experience, simplify the code writing and processing process, and improve performance and user experience. Whether it is event delegation or event interception, they need to be used flexibly and event propagation must be handled carefully to avoid potential problems. I hope the sample code and instructions in this article are helpful to you.

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