Writting in a file with javascript

SALAM all.
i'm programming a mobile app with sencha touch, and i need to save some information in a file (saved in the phone). I try this code which allows to write a file.txt with javascript but it doesn't work.

Code:

---

{
            xtype: 'button',
            flex: 1,
            margin: 10,
            text: 'Confirmer',
            handler: function()
            {
              Ext.Msg.confirm("Confirmation","Recharge de "+Ext.getCmp('num').getValue()+" Montant "+Ext.getCmp


('amount').getValue(),function(btn, text){
               
        if (btn == 'yes')
        {
        Ext.getCmp('resp').setValue("Recharge effectue");
        var file = new ActiveXObject("Scripting.FileSystemObject");
        var a = file.CreateTextFile("c:\\testfile.txt", true);
        a.WriteLine("SALAM WORLD !");
        a.Close();
        }
        else
        {
        Ext.getCmp('resp').setValue("Recharge annule");
        }
       
});
        //  Ext.getCmp('resp').setValue(btn);
            }   
       
          },

---

have you any idea how can i save few data of my mobile app in the phone for using it later.
thank you

Not sure exactly about the file reading and writing operations you have done is correct or not.
Why dont you try HTML's Localstorage that is supported by sencha or you can use cookies(better is localstorage).

SALAM.
thank you AKASH for your response. the wiritting function is correct, i show it in many web site. But i will test with the HTML localstorage.
thank you

plesure :)