jQuery Grid Plugin - jqGrid

I am trying to use jqGrid with JSON url but not able to use it. The htm page does not display any data.

Below is my code:

$(function () {
    "use strict";
    $('#list').jqGrid({
        datatype: 'json',
        url: 'json_url',
        caption: 'Prospect Finder',
        gridview: true,
        height: "auto",
        colNames: ['Partner','First Name', 'Last Name', 'Organization'],
        colModel: [
            {name: 'PARTNER', jsonmap: 'PARTNER' },
            {name: 'NAME_FIRST',jsonmap: 'NAME_FIRST' },
            {name: 'NAME_LAST', jsonmap: 'NAME_LAST' },
            {name: 'NAME_ORG1', jsonmap: 'NAME_ORG1' }
        ],
        jsonReader: {
            repeatitems: false,
            id: "PARTNER",
            root: function (obj) {
                return obj;
            }
        }
    });
});

And this is my JSON data

{"itab":[ { "PARTNER":"0061000220", "NAME_FIRST":"", "NAME_LAST":"", "NAME_ORG1":"GTA Central" }  ]}