MessageFrame:GetTimeVisible

Main Menu
WoW API Lua API FrameXML Widget API Widget scripts XML schema Events CVars Macro commands Combat Log Escape sequences Hyperlinks API changes HOWTOs wowuidev

Links
Blizzard Docs FrameXML  GitHub Search  Wowprogramming

Needs summary.

timeVisibleSeconds = MessageFrame:GetTimeVisible()

Returns

timeVisibleSeconds

number