Simple usage: procedure TMainForm.UniButton1Click(Sender: TObject); begin try Sleep(5000); finally JSInterface.JSCall('setDisabled', [False], (Sender as TUniButton).JSControl) end; end; procedure TMainForm.UniFormCreate(Sender: TObject); begin with UniButton1.JSInterface do begin JSConfig('_iconCls', ['x-fa fa-save']); JSConfig('iconAlign', ['right']); JSAddListener('disable', 'function(){this.setIconCls("x-fa fa-spinner fa-spin")}'); JSAddListener('enable',