Demo: https://iamdevonbutler.github.io/joinyoutubeclips
Basic:
?videoId=startTime-endTime
Multiple videos:
?felDULf1voY&AV1jKBrw0ck
Multiple segments:
?felDULf1voY=0-10,100-200
Autoplay on start:
#play
Segment time
To create a segment, the time values can be in seconds (90) and/or hh:mm:ss (1:30)