Why output is 2 ?

Question

Why output is 2 ?

var arr = [1,3,4,2];
var count = 0;
for(var x = 0;x <arr.length; x++)
{
x = arr[x];
count++;
}
document.write(count);

Answer 1

iteration | x | count
------------------------------------------------------------------------------
1 | 0 | 0
2 | x = arr[0] = 1 | count = count + 1 = 1
| x = x + 1 = 2 |
3 | x = arr[2] = 4 | count = count + 1 = 2
| x = x + 1 = 5 |

Answer 2

Output is 5!

Answer 3

Thanks.

Answer 4

Sorry my mistake,should be:
document.write(count);