先将字符串转成数组，用reverse（）翻转数组，再转成字符串
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<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head><body><div id="app"><h2> {{string}}</h2><button @click="reverse">逆转世界</button></div><script src="../../vue.js"></script><script>const app = new Vue({el: '#app',data: {string:'Hello,world',},methods:{reverse(){//先将字符串转成数组，用reverse（）翻转数组，再转成字符串this.string=this.string.split('').reverse().join('')}}})</script>
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