jQuery Grid Plugin - jqGrid

Hi,

I'm facing a problem by setting check all propery to jqgrid.

On my jqgrid instantiation i'm setting all checkbox as checked by using below code:

$('.cbox').attr('checked', true);

or

$('.cbox').trigger('click');


the problem i'm facing here is, while retrieving the value of selected checkbox using below code:
$("#mygrid").getGridParam("selarrrow");
it return me no value, rather it should return me the array of selected ids.