Using the following example as a base (from http://dev.sencha.com/deploy/dev/doc...=Ext.Container

Code:
// execute an Ajax request to invoke server side script:
Ext.Ajax.request({
    url: 'gen-invoice-grid.php',
    // send additional parameters to instruct server script
    params: {
        startDate: Ext.getCmp('start-date').getValue(),
        endDate: Ext.getCmp('end-date').getValue()
    },
    // process the response object to add it to the TabPanel:
    success: function(xhr) {
        var newComponent = eval(xhr.responseText); // see discussion below
        myTabPanel.add(newComponent); // add the component to the TabPanel
        myTabPanel.setActiveTab(newComponent);
    },
    failure: function() {
        Ext.Msg.alert("Grid create failed", "Server communication failure");
    }
});
Code:
(function() {
    function formatDate(value){
        return value ? value.dateFormat('M d, Y') : '';
    };

    var store = new Ext.data.Store({
        url: 'get-invoice-data.php',
        baseParams: {
            startDate: '01/01/2008',
            endDate: '01/31/2008'
        },
        reader: new Ext.data.JsonReader({
            record: 'transaction',
            idProperty: 'id',
            totalRecords: 'total'
        }, [
           'customer',
           'invNo',
           {name: 'date', type: 'date', dateFormat: 'm/d/Y'},
           {name: 'value', type: 'float'}
        ])
    });

    var grid = new Ext.grid.GridPanel({
        title: 'Invoice Report',
        bbar: new Ext.PagingToolbar(store),
        store: store,
        columns: [
            {header: "Customer", width: 250, dataIndex: 'customer', sortable: true},
            {header: "Invoice Number", width: 120, dataIndex: 'invNo', sortable: true},
            {header: "Invoice Date", width: 100, dataIndex: 'date', renderer: formatDate, sortable: true},
            {header: "Value", width: 120, dataIndex: 'value', renderer: 'usMoney', sortable: true}
        ],
    });
    store.load();
    return grid;  // return instantiated component
})();
Is it possible instead to have the ajax url point to a .js file on the server ? How would this .js file retrieve the parameters ?

Thanks