Ext JS - Exploitation de la réponse du serveur

Ext.onReady(function(){
    
    Ext.state.Manager.setProvider(new Ext.state.CookieProvider());

    var myData = [['Harold','Pinter'],['Randy','Pauch'],['Orhan','Pamuk'],['Toni','Morrison'],['Dorris','Lessing'],['Florence','Justina'],['Frank','Jennings'],['Dario','Fo'],['Ivan','Bunin'],['Henri','Bergson'],]

    var store = new Ext.data.ArrayStore({
        fields: [
           {name: 'FirstName'},
           {name: 'LastName'},
        ]
    });

    store.loadData(myData);

    var grid = new Ext.grid.GridPanel({
        store: store,
        columns: [
            {id:'FirstName',header: 'FirstName', width: 160, sortable: true, dataIndex: 'FirstName'},
            {header: 'LastName', width: 75, sortable: true, dataIndex: 'LastName'},
        ],
        stripeRows: true,
        height: 200,
        width: 600,
        title: 'Membres de la compagnie',
        stateful: true,
        stateId: 'grid'        
    });
    
    grid.render('exemple-table');
});

<?php

    $link=mysql_connect("127.0.0.1","root","") or die(mysql_error());
    mysql_select_db("airalliance") or die(mysql_error());
    $query="select * from guest order by LastName desc";
    $res=mysql_query($query);

    $reponse ="<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r";
    $reponse.="<dataset>\r";
    while ($data=mysql_fetch_array($res))
    {
        $reponse.="\t<row>\r";
        $reponse.="\t\t<FirstName>".$data['FirstName']."</FirstName>\r";
        $reponse.="\t\t<LastName>".$data['LastName']."</LastName>\r";
        $reponse.="\t</row>\r";
    }
    $reponse.="</dataset>\r";

    echo $reponse;
    mysql_close($link);

?>

Ext.onReady(function(){
   
    Ext.state.Manager.setProvider(new Ext.state.CookieProvider());

    var xmlhttpX
    xmlhttpX=GetXmlHttpObject();
    if (xmlhttpX==null)
    {
      alert ("Your browser does not support XMLHTTP!");
      return;
    }
    function GetXmlHttpObject()
    {
    if (window.XMLHttpRequest)
    {
      return new XMLHttpRequest();
    }
    if (window.ActiveXObject)
    {
      return new ActiveXObject("Microsoft.XMLHTTP");
    }
    return null;
    }
    xmlhttpX.open("GET","requete_table.php",false);
    xmlhttpX.send(null);
    var myData = xmlhttpX.responseXML

    var store = new Ext.data.XMLStore({
        fields: [
           {name: 'FirstName'},
           {name: 'LastName'},
        ]
    });

    store.loadData(myData);

    var grid = new Ext.grid.GridPanel({
        store: store,
        columns: [
            {id:'FirstName',header: 'FirstName', width: 160, sortable: true, dataIndex: 'FirstName'},
            {header: 'LastName', width: 75, sortable: true, dataIndex: 'LastName'},
        ],
        stripeRows: true,
        height: 200,
        width: 600,
        title: 'Membres de la compagnie',
        stateful: true,
        stateId: 'grid'        
    });
    
    grid.render('exemple-table');
});

Ext.onReady(function(){

    var store = new Ext.data.Store({

        url: 'sheldon.xml,

        reader: new Ext.data.XmlReader({
               record: 'Item',
               id: 'ASIN',
               totalRecords: '@total'
           }, [
               {name: 'Author', mapping: 'ItemAttributes > Author'},
               'Title', 'Manufacturer', 'ProductGroup'
           ])
    });

    var grid = new Ext.grid.GridPanel({
        store: store,
        columns: [
            {header: "Author", width: 120, dataIndex: 'Author', sortable: true},
            {header: "Title", width: 180, dataIndex: 'Title', sortable: true},
            {header: "Manufacturer", width: 115, dataIndex: 'Manufacturer', sortable: true},
            {header: "Product Group", width: 100, dataIndex: 'ProductGroup', sortable: true}
        ],
        renderTo:'example-grid',
        width:540,
        height:200
    });

    store.load();
});

var test = Ext.data.Record.create([
  {name:'nom', type:'string'},
  {name:'prenom', type:'string')
]);

var store = new Ext.data.Store({
  url: 'toto.php', //
  reader: new Ext.data.XmlReader({
    record:'untest',
  }, test),
  sortInfo:{field:'nom', direction:'ASC'}
});