Sys.WebForms.PageLoadedEventArgs panelsCreated Property
Gets an array of HTML div elements that represent UpdatePanel controls that were created when the DOM was updated during the last asynchronous postback.
Note
To get or set property values for client API properties, you must call property accessor methods that are named with the get_ and set_ prefixes. For example, to get or set a value for a property such as cancel, you call the get_cancel or set_cancel methods.
var arr = eventArgs.get_panelsCreated();
Return Value
An array of div elements that were created during the DOM manipulation that was caused by the last asynchronous postback. If no elements were created, the property returns null.
Remarks
If an UpdatePanel control is updated as a result of a partial-page update, the array referenced in the panelsCreated property of the PageLoadedEventArgs class contains a reference to the corresponding div element. The pageLoaded event of the Sys.WebForms.PageRequestManager class uses a PageLoadedEventArgs object to return its event data.