Sys.Application.enableHistory Property
Gets or sets a value that indicates whether the Web application supports history point management.
var historyEnabled = Sys.Application.enableHistory;
Return Value
true if the Web application supports adding history points to the browser's history stack; otherwise, false.
Remarks
Use the enableHistory property to enable history management in the Web application.
This property throws an exception if you try to set it after the Web application is initialized. It also throws an exception if history is enabled in the ScriptManager control and you try to disable it by using this property.