$event是指当前触发的是什么事件（鼠标事件，键盘事件等）
$event.target则指的是事件触发的目标，即哪一个元素触发了事件，这将直接获取该dom元素
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<!-- 引入库文件 -->
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
</head>
<body>
<div id="app">
<p>count的值为{{count}}</p>
<input type="button" value="按钮" @click="add($event,1)">
</div>
<script>
// 创建实例对象
const app = new Vue({
el: '#app',
data: {
count: 1
},
methods: {
add (e, a) {
console.log(e, a);
this.count += a
console.log(this.count);
if (this.count % 2 === 0) {
e.target.style.backgroundColor = 'pink'
} else {
e.target.style.backgroundColor = 'skyblue'
}
}
}
})
</script>
</body>
</html>
image.png
image.png
image.png
