jQuery Grid Plugin - jqGrid

i'm beginner in jqGrid Plugin. i Write this code:

var intArray = new Array(1000);
            var index = 1;

            var lastSel;
            var gridDocument = jQuery("#listDocument");
            gridDocument.jqGrid({
                url: 'jQGridHandler.ashx',
                postData: { ActionPage: 'ClearanceRequestDocument', Action: 'Fill', RequestId: '3' },
                ajaxGridOptions: { cache: false },

                datatype: 'json',
                height: '490',
                colNames: ['DocumentId', 'DocumentName', 'OrginalDocument','CopyDocument ', 'Remark'],
                colModel: [
                        { name: 'DOCUMENT_ID', width: 200, sortable: true, hidden: true },
                        { name: 'DOCUMENT_NAME', width: 200, sortable: true, editable: false },
                        { name: 'is_ORGINAL', width: 80, sortable: true, editable: true, formatter: 'checkbox', edittype: 'checkbox', editoptions: { value: 'Yes:No', defaultValue: 'Yes'} },
                        { name: 'is_copy', width: 80, sortable: true, editable: true, formatter: 'checkbox', edittype: 'checkbox', editoptions: { value: 'Yes:No', defaultValue: 'Yes'} },
                        { name: 'REMARK', width: 200, sortable: true, editable: false }
                ],

                sortname: 'DOCUMENT_ID',
                viewrecords: true,
                rownumbers: true,
                sortorder: "desc",
                editurl: 'clientArray',
                altRows: true,
                altclass: 'ui-priority-secondary',
                onSelectRow: function (id) {
                    if (id && id !== lastSel) {
                        gridDocument.saveRow(lastSel, true, 'clientArray');
                        gridDocument.jqGrid('restoreRow', lastSel);
                        gridDocument.jqGrid('editRow', id, true, null, null, 'clientArray');
                        lastSel = id;
                        intArray[index] = id;
                        index += 1;
                    }
                },
                pager: '#pagerDocument',
                rowNum: 30,
                rowList: [30, 60, 90],

                loadComplete: function () {
                    var $this = $(this), ids = $this.jqGrid('getDataIDs'), i, l = ids.length;
                    for (i = 0; i < l; i++) {
                        $this.jqGrid('editRow', ids[i], true);
                    }
                }
            }).jqGrid('navGrid', '#pagerDocument', { edit: false, add: false, del: false, search: false, refresh: false });

in this list i show all document and end user Should specify Documents delivered copy or original.i put Two CheckBox controls for each row .Now the user can Checked two CheckBox.But I want to be able to select any row a CheckBox. please help me expert. thanks all.