Algorithm for deleting duplicate data

This problem occurs at work: given an sorted array (in ascending order), the repeated data in the array can be deleted, but only one array can be used. The size of the array can be changed.
Example: array: [, 3,]
Output: [1, 2, 3, 4, 5, 7, 10]
Implementation (1 ):
Var arr = new Array );
Var len = arr. length;
For (var I = len-1; I> = 1; I --)
{
If (arr [I-1] = arr [I])
{
Arr. splice (I, 1 );
}
}
Alert (arr );

Implementation (2 ):
Var arr = new Array (, 3,); var len = arr. length; var k = 0; for (var I = 1; I <len; I ++) {if (arr [k]! = Arr [I]) {arr [k + 1] = arr [I]; k ++ ;}} alert (arr );
However, I find that the performance is not the best. I don't know if you have better algorithms. (The implementation language can be JavaScript, C #, VB.net ,.....)