I am using JQGrid 3.8.

This is my code:

var mydata = [ {id:"1",invdate:"2010-05-24",name:"test",note:"note",tax:"10.00",total:"2111.00"} ,
               {id:"2",invdate:"2010-05-25",name:"test2",note:"note2",tax:"20.00",total:"320.00"},
               {id:"3",invdate:"2007-09-01",name:"test3",note:"note3",tax:"30.00",total:"430.00"},
               {id:"4",invdate:"2007-10-04",name:"test",note:"note",tax:"10.00",total:"210.00"},
               {id:"5",invdate:"2007-10-05",name:"test2",note:"note2",tax:"20.00",total:"320.00"},
               {id:"6",invdate:"2007-09-06",name:"test3",note:"note3",tax:"30.00",total:"430.00"},
               {id:"7",invdate:"2007-10-04",name:"test",note:"note",tax:"10.00",total:"210.00"},
               {id:"8",invdate:"2007-10-03",name:"test2",note:"note2",amount:"300.00",tax:"21.00",total:"320.00"},
               {id:"9",invdate:"2007-09-01",name:"test3",note:"note3",amount:"400.00",tax:"30.00",total:"430.00"},
               {id:"11",invdate:"2007-10-01",name:"test",note:"note",amount:"200.00",tax:"10.00",total:"210.00"},
               {id:"12",invdate:"2007-10-02",name:"test2",note:"note2",amount:"300.00",tax:"20.00",total:"320.00"},
               {id:"13",invdate:"2007-09-01",name:"test3",note:"note3",amount:"400.00",tax:"30.00",total:"430.00"},
               {id:"14",invdate:"2007-10-04",name:"test",note:"note",amount:"200.00",tax:"10.00",total:"210.00"},
               {id:"15",invdate:"2007-10-05",name:"test2",note:"note2",amount:"300.00",tax:"20.00",total:"320.00"},
               {id:"16",invdate:"2007-09-06",name:"test3",note:"note3",amount:"400.00",tax:"30.00",total:"430.00"},
               {id:"17",invdate:"2007-10-04",name:"test",note:"note",amount:"200.00",tax:"10.00",total:"210.00"},
               {id:"18",invdate:"2007-10-03",name:"test2",note:"note2",amount:"300.00",tax:"20.00",total:"320.00"},
               {id:"19",invdate:"2007-09-01",name:"test3",note:"note3",amount:"400.00",tax:"30.00",total:"430.00"},
               {id:"27",invdate:"2007-10-04",name:"test",note:"note",amount:"200.00",tax:"10.00",total:"210.00"},
               {id:"28",invdate:"2007-10-03",name:"test2",note:"note2",amount:"300.00",tax:"20.00",total:"320.00"},
               {id:"29",invdate:"2007-09-01",name:"test3",note:"note3",amount:"400.00",tax:"30.00",total:"430.00"} ];
              
 jQuery("#list2").jqGrid({ data: mydata,
                            datatype: 'local',
                            height: 500,
                            rowNum: 30,
                            rowList: [10,20,30],
                            colNames:['Inv No','Date', 'Client', 'Amount','Tax','Total','Notes'],
                            colModel:[ {name:'id',index:'id', width:100, search:true, sorttype:"int"},
                                       {name:'invdate',index:'invdate', width:150, sorttype:"date", formatter:"date"},
                                       {name:'name',index:'name', width:100, editable:true},
                                       {name:'amount',index:'amount', width:80, align:"right",sorttype:"float", formatter:"number", editable:true},
                                       {name:'tax',index:'tax', width:80, align:"right",sorttype:"float", editable:true},
                                       {name:'total',index:'total', width:80,align:"right",sorttype:"float"},
                                       {name:'note',index:'note', width:150, sortable:false} ],
                           pager: '#pager2',
                           viewrecords: true,
                           sortorder: "desc",
                           grouping:true,   
                           caption: "Grouping Array Data" }).navGrid('#pager2',{edit:false,add:false,del:false});