JS实现随机抽取三人

for (var i=0;i<3;i++) {
  index1 = Math.round(Math.random()(array.length-1));
  value = array[index1];

  newarray.push(value);
  array.splice(index1,1);

  value ='';
 }
 console.log(newarray);

 for (var j =0;j<newarray.length;j++) {
  for (var m = 0; m < arr1.length; m++) {
   if (newarray[j] === arr1[m]){
    num1++;
   }
  }
  for (var n = 0; n < arr2.length; n++) {
   if (newarray[j] === arr2[n]){
    num2++;
   }
  }
  for (var o = 0; o < arr3.length; o++) {
   if (newarray[j] === arr3[o]){
    num3++;
   }
  }
 }
 btn.onclick = function (){


 var id = setInterval(frame,500);
 function frame() {
  if (!flag) {
   clearInterval(id);
   flag=true;
  } else {
   Begin();
   document.getElementById("name").innerHTML="";
   for (var i = 0; i < newarray.length; i++) {
    document.getElementById("name").innerHTML += newarray[i] + "</br> ";

   }
   flag=false;
   newarray=[];
  }
 }

}

function Begin() {
  num1 = Math.round(Math.random()  (arr4.length - 1));
  num2 = Math.round(Math.random()  (arr4.length - 1));
  num3 = Math.round(Math.random()  (arr4.length - 1));
  Begin2();
 }

 function Begin2() {
  var array = [];
  var arrayLast = [];
  if (num1 !== num2 && num1 !== num3 && num2 !== num3) {
   array.push(num1);
   array.push(num2);
   array.push(num3);
   for (var i = 0; i < array.length; i++) {
    if (typeof arr4[array[i]] === "string") {
     arrayLast.push(arr4[array[i]]);
    } else {
     var num4 = Math.round(Math.random()  (arr4[array[i]].length - 1));
     arrayLast.push(arr4[array[i]][num4]);
    }
   }
  } else {
   Begin();
  }

  console.log(arrayLast);
  document.getElementById("name").innerHTML="";
  for (var i = 0; i < arrayLast.length; i++) {
   document.getElementById("name").innerHTML += arrayLast[i] + "</br> ";
  }
 }

 btn.onclick = function () {
  Begin();

 }