jQuery Grid Plugin - jqGrid

Hi,

I m using jquery validationengine plugin in jqgrid to validate each fileds while adding and editing fields, its working fine but the thing is it will submit the form  please lookout this code and help me out on this

jQuery(document).ready(function(){
jQuery("#list").jqGrid({
url:'server.php',
datatype: "json",
mtype: 'POST',

colNames:['Sap Id','Emp ID','Employee Name','Roles','Location','Group Name','Email'],
colModel:[
       {name:'sap_id', index:'sap_id', width:20, align:'left',
              searchoptions:{sopt:['eq', 'ne','cn','nc']},
              editable:true

              },

       {name:'emp_id', index:'emp_id', width: 40, align:'left',
              searchoptions:{sopt:['eq', 'ne','cn','nc'],searchhidden:true},hidden: true ,editrules: {edithidden:true,"class":"validate[required,custom[onlyLetterSp]] text-input"},
              editable:true,editoptions:{"class":"validate[required,custom[onlyLetterSp]] text-input"}
              },

       {name:'name', index:'name', width:50, align:'left',
              search : false,
              editable:true,editoptions:{"class":"validate[required,custom[onlyLetterSp]] text-input"}
              },

       {name:'roles', index:'roles', width:30, align:'left',
              search : false,editable:true,edittype:'custom',editoptions:{ custom_element:MultiCheckElem, custom_value:MultiCheckVal, list:'User,Manager,PMO',recreateForm: true,"class":"validate[required]"
              }},

       {name:'location', index:'location', width:20, align:'left',
                    searchoptions:{sopt:['eq', 'ne','cn','nc']},resizable:true,
              editable:true,edittype:'select',editoptions:{ value:getlocation(),
              "class":"validate[required]"}
              },

       {name:'groupname', index:'groupname', width:35, align:'left',
              search : false,resizable:true,
              editable:true,edittype:'select',editoptions:{value:getgroups(),"class":"validate[required]"}
              },

       {name:'email', index:'email', width: 35, align:'left',
              searchoptions:{sopt:['eq', 'ne','cn','nc']},
              editable:true,editoptions:{"class":"validate[required,custom[email]]"}
              },
       ],

jQuery.extend(jQuery.jgrid.edit, {
    onclickSubmit : function(params,postdata) {

              jQuery(document).ready(function(){
                           // binds form submission and fields to the validation engine
                          if(!jQuery("#FrmGrid_list").validationEngine('validate')){

                                  return false;

                          }

             });
  },

  afterComplete : function (response, postdata, formid) {

          if (postdata.oper === "add") { // highlight on "add" only
              var row = jQuery ("#"+$.jgrid.jqID(postdata.id), jQuery(this.gbox));
              row.effect("highlight", {color:"red"}, 3000);
          }
      },

  afterclickPgButtons: function(whichbutton, formid, rowid) {
          var rolename = $('#list').getCell(rowid,4)
          if(rolename ==="User") {
            document.getElementsByName("roles")[0].checked = true;
          }

          if(rolename ==="User/Manager") {
                    document.getElementsByName("roles")[0].checked = true;
                    document.getElementsByName("roles")[1].checked = true;
          }

          if(rolename==="User/Manager/PMO") {
                    document.getElementsByName("roles")[0].checked = true;
                    document.getElementsByName("roles")[1].checked = true;
                    document.getElementsByName("roles")[2].checked = true;
         }
 },

 onClose: function(params, posdata) {
      $(".formError").detach();
    },
    clearAfterAdd :false,
    closeAfterAdd: true,
    closeAfterEdit:true,
    recreateForm: true,

 });

Thanks in advacce