jQuery Grid Plugin - jqGrid

SORRY I MENT NAVGRID SEARCH

after introducing some value inside the search form and pressing the button Find, I get the correct return result into the PHP code in json (echo json_encode($responce);) but the grid doesnt repopulate with the new data and keeps the old one. This is the in the HTML part :

$(function(){

$("#list").jqGrid({ url:'search.php?q=1′,

datatype: 'json',

height: '500′,

width : '920′,

autowidth: "false",

shrinkToFit: "true",

mtype: 'POST',

colNames:['Articolo','Marchio', 'Collection'],

colModel :[

{name:'Articolo', index:'Articolo', width:400},

{name:'Marchio', index:'Marchio', width:400},

{name:'Collection', index:'Collection', width:400, align:'right'}

, ],

pager: '#pager',

rowNum:30,

rowList:[30,60,90],

sortname: 'Articolo',

sortorder: 'asc',

viewrecords: true,

gridview: true,

caption: 'Test' });

jQuery("#list").jqGrid('navGrid','#pager',{add:true,edit:true,del:true}); });

What's wrong ? Shall I use a trigger or reload or what ? Sorry for the stupid question but I'm reading the manual of version 3.4 and I can't find any answer. Actually the server doesnt pass to jqGrid the filtered data All this only works with loadonce:true, Can you give me a Hint ? Thanks