事件處理機制的三個階段(捕獲階段,目標階段,冒泡階段)
冒泡階段:事件從內向外執行捕獲階段:事件從外向內執行;
- addEventListener(type,fn,useCapture)
- useCapture:事件處理機制(捕獲階段true,目標階段,冒泡階段false)默認爲冒泡階段
- 捕獲階段:事件從外向內執行; 冒泡階段:事件從內向外執行
捕獲情況:
<style>
#parent{
height: 300px;
width: 300px;
background-color: red;
}
#son{
height: 100px;
width: 100px;
background-color: green;
}
</style>
</head>
<body>
<div id="parent">
<div id="son"></div>
</div>
</body>
<script>
document.getElementById('parent').addEventListener('click',function(e){
console.log('是你爸爸')
},true)
document.getElementById('son').addEventListener('click',function(e){
console.log('你兒子')
},true)
</script>
冒泡情況:
<style>
#parent{
height: 300px;
width: 300px;
background-color: red;
}
#son{
height: 100px;
width: 100px;
background-color: green;
}
</style>
</head>
<body>
<div id="parent">
<div id="son"></div>
</div>
</body>
<script>
document.getElementById('parent').addEventListener('click',function(e){
console.log('是你爸爸')
},false)
document.getElementById('son').addEventListener('click',function(e){
console.log('你兒子')
},false)
</script>
阻止冒泡行爲:
<style>
#parent{
height: 300px;
width: 300px;
background-color: red;
}
#son{
height: 100px;
width: 100px;
background-color: green;
}
</style>
</head>
<body>
<div id="parent">
<div id="son"></div>
</div>
</body>
<script>
document.getElementById('parent').addEventListener('click',function(e){
console.log('是你爸爸')
},false)
document.getElementById('son').addEventListener('click',function(e){
console.log('你兒子')
e.stopPropagation() // 阻止冒泡
},false)
</script>
阻止冒泡行爲的兼容性:
非 IE8及以下瀏覽器 使用 e.stopPropagation()
IE8及以下瀏覽器 使用 window.event.cancelBubble = true