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How to use event bubbling to achieve more efficient event processing
Event bubbling means that events are triggered starting from the most specific element, and then propagated upward to more General elements. In front-end development, correct use of event bubbling can achieve more efficient event processing. This article will introduce the principle of event bubbling, and show how to use event bubbling to achieve more efficient event processing through specific code examples.
1. The principle of event bubbling
Event bubbling is an event propagation mechanism defined in the DOM specification. When a specific event occurs on an element in the DOM tree, the event will first be triggered on the triggering element, then bubble up level by level, and finally propagate to the root node of the DOM tree.
Event bubbling has the following characteristics:
2. Sample code
The following sample code demonstrates how to use event bubbling to achieve more efficient event processing.
<div id="parent"> <div id="child1"> <button id="btn1">按钮1</button> </div> <div id="child2"> <button id="btn2">按钮2</button> </div> <div id="child3"> <button id="btn3">按钮3</button> </div> </div> <script> // 监听父元素的click事件 document.getElementById('parent').addEventListener('click', function (event) { // 获取被点击的按钮的id var targetId = event.target.id; // 根据id执行相应的逻辑 switch (targetId) { case 'btn1': console.log('按钮1被点击了'); break; case 'btn2': console.log('按钮2被点击了'); break; case 'btn3': console.log('按钮3被点击了'); break; default: break; } }); </script>
In the above code, we listen to the click event on the parent element. When the button in the child element is clicked, the event will bubble up to the parent element, and then the corresponding logic will be executed by judging the id of the clicked button. In this way, we can avoid binding an event handler to each button, allowing for more efficient event handling.
3. Advantages of event delegation
Using event delegation to monitor events on the parent element can not only achieve more efficient event processing, but also have the following advantages:
4. Notes
When using event bubbling to achieve more efficient event processing, you need to pay attention to the following points:
event.stopPropagation()
. Summary:
By rationally utilizing event bubbling, we can achieve more efficient event processing. Through the analysis of code examples, we can clearly understand the principle of event bubbling and how to use event delegation to achieve more efficient event processing. At work, we should make full use of the event bubbling mechanism, optimize our event processing logic, and improve the performance and user experience of the front-end page.
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