I had a hard time finding the English origin of this interjection and how it technically should be written. I am often ridiculed in written conversations, especially those that are informal, because I might reply to something funny with, "Ha ha ha." It seems as if the accepted way to colloquially spell this is "hahaha."
When asked about it, I actually admitted that the original spelling might have been something like "ha-ha-ha," similar to how "goodbye" seems to have been originally written as "good-bye."
What is the correct way?