jQuery Grid Plugin - jqGrid

Hi, my grid has column 'member', which is checkbox column, always avaliable to change.

colModel: [
    { name: 'member', index: 'member', width: 80, search: false, align: 'center', formatter: 'checkbox', editoptions: { value: '1:0' }, formatoptions: { disabled: false} },
    { name: 'group', index: 'group', width: 150, editable: false },
    { name: 'groupdesc', index: 'groupdesc', width: 220, editable: true, search: false }
],

User then selects checkboxes and while pressing a save button a ajax call will be made. The problem is, that I do not know how to retrieve (changed) cell data.

This allways returns initial values (not changed):

for (i = 0; i < 5; i++) {

       var rowid = $('#gGroups')[0].rows[i].id
       var myceldata = $('#gGroups').getCell(rowid, 0);

}

// mycelldata gets always: <input value="false" offval="no" type="checkbox">

thank you for reply