Optional
errThe error (exception) which occurred while executing the original method
Optional
evtThe Event object from (window.event) at the start of the original call
Optional
rsltThe result of the original method, only populated after the original method has returned
Allows the hook functions to replace the original arguments
The argument index (0 based)
The new value for the argument
This returns an object that the hook function can use to store hook specific context, it it not shared with any other hook instances and is unique for the current call. A hook implementation can use this to pass / share context between different hook callbacks eg. request/response requst/hookErrors etc.