先看代码:
<html>
<head>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
<button @click="sub">-</button>
<span>{{number}}</span>
<button @click="add">+</button>
</div>
<script>
var app = new Vue({
el: '#app',
data: {
number: 0
},
methods: {
sub: function () {
if (this.number != 0) {
this.number -= 1;
} else {
alert("不能再减少了");
}
},
add: function () {
if (this.number < 10) {
this.number += 1;
} else {
alert("不能再增加了");
}
},
},
})
</script>
</body>
</html>
结果:
点击加号会一直增加数量,当加到10之后再点击:
点击减号可以减少数量,当数量为0时再点击: