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JavaScript事件冒泡和捕获模式

hwwjian 2022-11-08 阅读 124

JavaScript事件冒泡和捕获模式_html

捕获模式

1,addEventListener的第三个参数useCapture为true则为捕获模式
2,单击C时事件触发顺序为A-> B-> C

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
.a {
background: lightblue;
padding: 50px;
}
.b {
background: lightgray;
padding: 50px;
}
.c {
background: lightyellow;
padding: 50px;
}
</style>
</head>
<body>
<div class="a">
A
<div class="b">
B
<div class="c">
C
</div>
</div>
</div>
</body>
<script>
var a = document.querySelector('.a')
var b = document.querySelector('.b')
var c = document.querySelector('.c')
a.addEventListener('click', function(event){
console.log('capture click a')
}, true)
b.addEventListener('click', function(event){
console.log('capture click b')
}, true)
c.addEventListener('click', function(event){
console.log('capture click c')
}, true)
</script>
</html>

JavaScript事件冒泡和捕获模式_事件触发_02


冒泡模式

1,不填充addEventListener的第三个参数为冒泡模式
2,单击C时事件触发顺序为C-> B-> A

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
.a {
background: lightblue;
padding: 50px;
}
.b {
background: lightgray;
padding: 50px;
}
.c {
background: lightyellow;
padding: 50px;
}
</style>
</head>
<body>
<div class="a">
A
<div class="b">
B
<div class="c">
C
</div>
</div>
</div>
</body>
<script>
var a = document.querySelector('.a')
var b = document.querySelector('.b')
var c = document.querySelector('.c')
a.addEventListener('click', function(event){
console.log('Bubble click a')
})
b.addEventListener('click', function(event){
console.log('Bubble click b')
})
c.addEventListener('click', function(event){
console.log('Bubble click c')
})
</script>
</html>


JavaScript事件冒泡和捕获模式_html_03

取消冒泡

// 取消冒泡
event.cancelBubble = true

1,取消冒泡后事件就不会往上层传递
2,这时只有监听C的事件被执行

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
.a {
background: lightblue;
padding: 50px;
}
.b {
background: lightgray;
padding: 50px;
}
.c {
background: lightyellow;
padding: 50px;
}
</style>
</head>
<body>
<div class="a">
A
<div class="b">
B
<div class="c">
C
</div>
</div>
</div>
</body>
<script>
var a = document.querySelector('.a')
var b = document.querySelector('.b')
var c = document.querySelector('.c')
a.addEventListener('click', function(event){
console.log('Bubble click a')
})
b.addEventListener('click', function(event){
console.log('Bubble click b')
})
c.addEventListener('click', function(event){
console.log('Bubble click c')
event.cancelBubble = true
})
</script>
</html>


JavaScript事件冒泡和捕获模式_事件触发_04


本文完~

JavaScript事件冒泡和捕获模式_事件触发_05

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