How to copy and randomize copied elements in the same loop?

I'm try to copy the even numbers in an array and randomize the newly copied element inside the same for loop:

<script>
  var arr=[0,1,2,3,4,5,6,7,8];
  var arr2=[];
  for(var i=0;i<arr.length;i++){
    if(arr[i]%2==0){
      arr2.splice(Math.random()*arr2.length,0,arr[i]);
    }
  }
  document.write(arr2);
</script>

The concept is simple:insert the newly copied element at random position of the new array, but the serval output indicates it's not correct:

2,6,4,8,0
4,8,6,2,0
6,2,8,4,0

which always have 0 at the last. What's wrong with the code? Or is my concept wrong?