[Update because this answer seems to get some views] --
Updated Answer:
In later versions (I believe 1.10+), the API naming conventions changed, ditching the Hungarian notation. I believe the old conventions are aliased for compatibility, but the current conventions are:
lengthMenu
pageLength
Thus, the updated answers are:
A) it's the lengthMenu
parameter: https://datatables.net/reference/option/lengthMenu
For example, here's how I have one of mine set:
"lengthMenu": [[10, 25, 50, 100, 200, -1], [10, 25, 50, 100, 200, "All"]],
B) pageLength https://datatables.net/reference/option/pageLength -- optionally set this to whatever your default should be.
"pageLength" : 25,
Original Answer
A) It's the aLengthMenu
parameter: http://datatables.net/ref#aLengthMenu
For example, here's how I have one of mine set:
"aLengthMenu": [[10, 25, 50, 100, 200, -1], [10, 25, 50, 100, 200, "All"]],
B) iDisplayLength
-- set this parameter to whatever your default should be