SetTitleMatchMode 2

#IfWinExist - YouTube
    ^m::YouTubeKeys("m") ; Mute
    ^k::YouTubeKeys("k") ; Play/Pause
    ^j::YouTubeKeys("j") ; Seek backward
    ^l::YouTubeKeys("l") ; Seek forwards
#IfWinExist

YouTubeKeys(Key)
{
    KeyWait, % "{" Key "}"
    ControlFocus
    ControlSend ahk_parent, % "{" Key "}"
}