Setting the following:

Change all elements in the array in places, that is, the one that was 10th, Make 1st. The one was 9th, make 2nd and so on.

I do and nothing works, more precisely the first five changes and then not.
Here is the code:

var arr = new array (1,2,3,4,5,6,7,8,9, ten);
var arr_2 = arr;
var i = 0;
VAR Count = Arr.Length;
for (i = 0; i & lt; arr.length; i ++) {
  Document.Write (Arr [i] + '');
}
Count = Count-1;
i = 0;
for (i = 0; i & lt; arr.length; i ++) {
   ARR [i] = ARR [COUNT];
   ARR [COUNT] = ARR_2 [I];
   Count = Count-1;
}
Document.Write ('& lt; br & gt;');
for (i = 0; i & lt; arr.length; i ++) {
  Document.Write (Arr [i] + '');
}

1, Authority 100%

I’ll just leave it to do: http://javascript.ru/array/reverse

2, Authority 14%

Well, as BE, you need another variable here

for (i = 0; i & lt; = count / 2; i ++) {
   var t = arR [COUNT-I];
   ARR [COUNT-I] = ARR [I];
   Arr [i] = T;
}

And then you have arrays – this is the same object as it is created through New.

Learn the programming language on which you write

3, Authority 7%

As I understand it at the start), respectively, you need the easiest solution without methods, here it is:

for (i = arr.length-1; i & gt; = 0; i--) {
  Document.Write (Arr [i] + '');
}

4, Authority 7%

Here this option

var arr = [0,1,2,3,4,5,6,7,8,9] ;
VAR TEMP;
for (var i = 0, j = arr.length-1; i & lt; j; i ++, j--)
{
  temp = arr [j];
  arr [j] = arr [i];
  ARR [I] = TEMP;
}
Document.getelementByid ('Result'). Innerhtml = (ARR);

At one time, in the first year, success was due to the use of complexity O (N / 2) .

is not always inferior to the built-in array.reverse ()

Pruf

5, Authority 7%

Try it:

arr.reduce ((p, c) = & gt; {c + = p; return c;}, '' ) .split``;

and what changes are simply analog.

6

If you do not want to use Sort or the second variable, then this is such a parsley:

var arr = new array (1,2,3,4,5,6,7,8,9, ten);
var newarr = [], index;
For (i = arr.length; i & gt; 0; i--) {
  index = Arr.Length - I;
  newArr [i] = Arr [index];
}
Console.log (NewArr);

7

function sortfunction (a, b) {
  IF (A & LT; B)
   Return 1;
  if (a & gt; b)
   Return -1;
  Return 0.
}
Var Arr = New Array (1,2,3,4,5,6,7,8,9,10);
Console.log (Arr.Sort (SortFunction));

Now in Russian. JavaScript has the SORT method in which we pass our sort function. Read more here