Found the solution:

add this code:

jQuery("#navgrid").jqGrid('navGrid','#pagernav',
{edit:true,add:false,del:false, search:false}, //options
{ height:360,reloadAfterSubmit:false, top:100,
afterShowForm : hookDatePicker }, // edit options

{sopt:['cn','bw','eq','ne','lt','gt','ew']} // search options
);

and declare a function to threat the event:

function hookDatePicker(formID)
{


I have been trying for a while to change the layout of the edit grid .. but i really need the help. Is their any way other than selecting all the tr by id and changing the html ?