How to create ExtJS elements with dynamic id ExtJs 3.0?

Question

At a time in function need to pass with id and without id(null).Static it is working but how i will make this in dynamic. Here winCreatePand is model window id.

{ xtype: 'button',
text: 'Generate',
id: 'btnGenerate',
width: 65,
style: 'margin-left: 10px',
handler: function()
{ PandDataProvider.GetPandId();
PandDataProvider.GetPandId('winCreatePand');
},
scope: this
}