I learned a bit of HTML a few years ago and I have a vague recollection about reading something about "user made tags" but I can't find anything.
My question: Is it acceptable to define an HTML tag, for example <H23></H23> or <Ha></Ha>? My vague recollection is that HTML would consider it as invalid and ignore it which would be perfect for what I want to do because this tag can be used by scripts.
If you have a better idea to achieve the same goal then I'd definitely welcome your examples.
Thank you for your help.