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What is the meaning of bubbling events
- PHPzOriginal
- 2024-02-19 11:53:22428browse
Bubbling events mean that in web development, when an event is triggered on an element, the event will propagate to the upper element until it reaches the document root element. This propagation method is like a bubble gradually rising from the bottom, so it is called a bubbling event.
In actual development, it is very important to understand and understand the working principle of bubbling events to handle events correctly. The following will introduce the concept and usage of bubbling events in detail through specific code examples.
First, we create a simple HTML page with a parent element and three child elements:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>冒泡事件示例</title>
</head>
<body>
<div id="parent">
<div id="child1">子元素1</div>
<div id="child2">子元素2</div>
<div id="child3">子元素3</div>
</div>
</body>
</html>Next, we use JavaScript to add event handlers and trigger bubbling events .
// 获取父元素和子元素的引用
var parent = document.getElementById("parent");
var child1 = document.getElementById("child1");
var child2 = document.getElementById("child2");
var child3 = document.getElementById("child3");
// 添加点击事件处理程序
parent.addEventListener("click", function(event) {
console.log("父元素被点击了");
});
child1.addEventListener("click", function(event) {
console.log("子元素1被点击了");
});
child2.addEventListener("click", function(event) {
console.log("子元素2被点击了");
});
child3.addEventListener("click", function(event) {
console.log("子元素3被点击了");
});In the above code, we added a click event handler for each element by calling the addEventListener method. When an element is clicked, the corresponding event handler will print out the corresponding prompt information.
Next, let’s test whether the bubbling event takes effect. Click on child element 1, we will find that in addition to the prompt information of child element 1, the prompt information of the parent element being clicked will also be printed. This is because bubbling events will propagate to the parent element, triggering all click events.
Similarly, when we click on child element 2, the prompt information that child element 2 was clicked and the parent element was clicked will be printed; when we click child element 3, the message that child element 3 was clicked and the parent element will be printed out. Prompt message when the element is clicked.
To summarize, a bubbling event means that when an event is triggered on an element, the event will propagate to the upper elements step by step and trigger the event handler on each element in turn. By understanding how bubbling events work, we can handle events more flexibly and improve the efficiency and user experience of web development.
The above is an introduction and specific code examples about bubbling events. I hope it will be helpful to readers in understanding and applying bubbling events.
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