Js : Set field items for each items I create

Question

I would like to set manually each items when I create them. I'm a newbie in Js but I search for a long time and no find the answer : I need some help please. When I make a new annonce, how reach each field ?

function annonce() { return {
   // scroll: 'vertical',
    items: [{
        xtype: 'fieldset',
        title: 'Annonce',
        items: [{
            xtype: 'textfield',
            id:'titre'
            label: 'Vente', 
        },
        {
            xtype: 'urlfield',
            id: 'contact',
            label: 'Contact',
            //placeholder: 'Steve Jobs'
        }]
    }]
};
}

var card = new Ext.Panel({
scroll: 'vertical',
    activeItem: 0, // make sure the active item is set on the container config!
    bodyStyle: 'padding:15px',
    defaults: {
        // applied to each contained panel
        border:false
    },
    // just an example of one possible navigation scheme, using buttons
       // the panels (or "cards") within the layout
    items: [    
    new annonce({
        id: 'card-0',
        title: 'test1', 
        Ext.getCmp('titre').setValue('mac');       // <-- don't work
    }),
    new annonce({
        id: 'card-1',
        Ext.getCmp('titre').setValue('rolls');     // <-- don't work
    }),
    new annonce({
        id: 'card-2'        
    })]
});



demos.Forms = card;