Change jquery datatables default row count shown

[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

• DataTables 1.10+

  Use lengthMenu to define a list of available page lengths and optionally pageLength to set initial page length.

  If pageLength is not specified, it will be automatically set to the first value given in array specified by lengthMenu.

  var table = $('#example').DataTable({
     lengthMenu: [ [2, 4, 8, -1], [2, 4, 8, "All"] ],
     pageLength: 4
  });
  

  See this jsFiddle for code and demonstration.

---

• DataTables 1.9

  Use aLengthMenu to define a list of available page lengths and iDisplayLength to set initial page length.

  var table = $('#example').dataTable({
     "aLengthMenu": [ [2, 4, 8, -1], [2, 4, 8, "All"] ],
     "iDisplayLength" : 4,        
  });
  

  See this jsFiddle for code and demonstration.