:-) I fixed it.Actually it was my mistake.Because I forgot to add javascript links
<link rel="stylesheet" type="text/css" media="screen" href="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.16/themes/redmond/jquery-ui.css" />
<link rel="stylesheet" type="text/css" media="screen" href="themes/ui.jqgrid.css" />
<script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.7.1.min.js" type="text/javascript"></script>
<script src="js/trirand/i18n/grid.locale-en.js"type="text/javascript"></script>
<script src="js/trirand/jquery.jqGrid.min.js" type="text/javascript"></script>