var sort = function(arr){
  for(var i = 0; i < arr.length-1; i ++){
    for(var j = i+1; j < arr.length; j++){
      if(arr[i]>arr[j]){
        var temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
      }
    }
  }
};

var arr = [5,4,3,2,1,0];
console.log("before sort" + arr);
sort(arr);
console.log("after sort " + arr);