How to use the "onchange" event of the text components?

{ 
type: 'text', label: 'search', value: '', position: 'label-left',popup: 'searchPanel',
[b]onchange:'searchText_change'[/b], width: 600, labelWidth: 80, 
align: 'left', labelAlign: 'left', 
id: 'searchText'
}

My Friend,Pls tell me!

unfortunately, there is not public method to set onchange event handler for the text component

Anyway, thank you for your help!