The source code

    Ext.onReady(function(){

        var store = new Ext.data.Store({
            remoteSort: true,
            baseParams: {lightWeight:true,ext: 'js'},
            sortInfo: {field:'lastpost', direction:'DESC'},
            autoLoad: {params:{start:0, limit:500}},

            proxy: new Ext.data.ScriptTagProxy({
                url: 'http://extjs.com/forum/topics-browse-remote.php'
            }),

            reader: new Ext.data.JsonReader({
                root: 'topics',
                totalProperty: 'totalCount',
                idProperty: 'threadid',
                fields: [
                    'title', 'forumtitle', 'forumid', 'author',
                    {name: 'replycount', type: 'int'},
                    {name: 'lastpost', mapping: 'lastpost', type: 'date', dateFormat: 'timestamp'},
                    'lastposter', 'excerpt'
                ]
            })
        });

        var grid = new Ext.grid.GridPanel({
            renderTo: 'topic-grid',
            width:700,
            height:500,
            frame:true,
            title:'ExtJS.com - Browse Forums',
            trackMouseOver:false,
    		autoExpandColumn: 'topic',
            store: store,

            columns: [new Ext.grid.RowNumberer({width: 30}),{
                id: 'topic',
                header: "Topic",
                dataIndex: 'title',
                width: 420,
                renderer: renderTopic,
                sortable:true
            },{
                header: "Replies",
                dataIndex: 'replycount',
                width: 70,
                align: 'right',
                sortable:true
            },{
                id: 'last',
                header: "Last Post",
                dataIndex: 'lastpost',
                width: 150,
                renderer: renderLast,
                sortable:true
            }],

    	    bbar: new Ext.PagingToolbar({
    		    store: store,
    		    pageSize:500,
    		    displayInfo:true
    	    }),

    	    view: new Ext.ux.grid.BufferView({
    		    // custom row height
    		    rowHeight: 34,
    		    // render rows as they come into viewable area.
    		    scrollDelay: false
    	    })
        });

        // render functions
        function renderTopic(value, p, record){
            return String.format(
                    '{0}{1} Forum',
                    value, record.data.forumtitle, record.id, record.data.forumid);
        }
        function renderLast(value, p, r){
            return String.format('{0}
    by {1}', value.dateFormat('M j, Y, g:i a'), r.data['lastposter']);
        }

    });