Problem with $find on TabContainer using Master Pages

If you've placed your TabContainer on a page using a Master page you can't get the behaviour of the TabContainer the usual way (which would work on a page without master):

var tabContainer = $find('TabContainer1');

Therefore, if your page has a Master Page you must instead use the $get method and send the UniqueId of the TabContainer as a parameter. Through the retrurned object, you can get the control object which represents the behaviour of the TabContainer:

var tabContainer = $get('<%= this.TabContainer1.ClientID%><%= TabPassengerInfo.ClientID%>').control;