vue简易跑马灯

var vm=new Vue({

           el:'#app',

           data:{

               msg:'你好！vue',

               timer:null

           },

           methods:{

               handlerClick(){

                //    var _this=this;

                   console.log(this.timer)

                   if(this.timer){ //在全局中定义一个timer

                       return;

　　　　　　}

                   this.timer=setInterval(()=>{//箭头函数没有自己的this，自动寻找到外层的this，即寻找到回到函数的this

                        var startStr=this.msg.substring(0,1);

                        var endStr=this.msg.substring(1);

                        this.msg=endStr+startStr;

                        

                   },1000);

               },

               stopClick(){

                   if(this.timer){

                       clearInterval(this.timer);

                       this.timer=null;

                   }

               }

           }

       })