[Freeswitch-users] get BYE event in javascripts

Hi all, I have a simple javascripts with simple scenario. In this scenario, user can listen audio and send dtmf to play next or previous audio file. When user send dtmf to play other audio file, I will store play time of this audio to a text file (time.txt), but, if user hangup this call, the play time of last file cannot store in time.txt. How I can capture event user hangup to store play time into time.txt before javascripts session destroyed? Brs, Khue.