js判断数组中是否有重复数据

var arr=[1,3,5,7,9,9,10,10,11,12,34,3,6,92,1];
var tempbool = false; //默认无重复
        for (let index = 0; index < arr.length; index++) {
          for (let i = index+1; i < arr.length; i++) {
            if ( arr[index]== arr[i] ) {
              tempbool = true;
            }
          }
        }
        if (tempbool) {
         console.log('存在重复数据！');
        }