绑定样式：
1. class样式写法:class="xxx" xxx可以是字符串、对象、数组。字符串写法适用于：类名不确定，要动态获取。对象写法适用于：要绑定多个样式，个数不确定，名字也不确定。数组写法适用于：要绑定多个样式，个数确定，名字也确定，但不确定用不用。2. style样式:style="{fontSize: xxx}"其中xxx是动态值。:style="[a,b]"其中a、b是样式对象。
<!DOCTYPE html>
<html><head><meta charset="UTF-8" /><title>绑定样式</title><style>.basic{width: 400px;height: 100px;border: 1px solid black;}.happy{border: 4px solid red;;background-color: rgba(255, 255, 0, 0.644);background: linear-gradient(30deg,yellow,pink,orange,yellow);}.sad{border: 4px dashed rgb(2, 197, 2);background-color: gray;}.normal{background-color: skyblue;}.ata1{background-color: yellowgreen;}.ata2{font-size: 30px;text-shadow:2px 2px 10px red;}.ata3{border-radius: 20px;}</style><script type="text/javascript" src="../js/vue.js"></script></head><body><div id="root"><div class="basic" :class="mood" @click="changeMood">{{name}}</div> <br/><br/><div class="basic" :class="classArr">{{name}}</div> <br/><br/><div class="basic" :class="classObj">{{name}}</div> <br/><br/><div class="basic" :style="styleObj">{{name}}</div> <br/><br/><div class="basic" :style="styleArr">{{name}}</div></div></body><script type="text/javascript">Vue.config.productionTip = falseconst vm = new Vue({el:'#root',data:{name:'123',mood:'normal',classArr:['ata1','ata2','ata3'],classObj:{ata1:false,ata2:false,},styleObj:{fontSize: '40px',color:'red',},styleObj2:{backgroundColor:'orange'},styleArr:[{fontSize: '40px',color:'blue',},{backgroundColor:'gray'}]},methods: {changeMood(){const arr = ['happy','sad','normal']const index = Math.floor(Math.random()*3)this.mood = arr[index]}},})</script></html>
