Well, the music form called "jazz" extends from some years before the first recordings in 1917, to now, and includes many styles of performance. Just a brief listing of most of the most important:
Early jazz (Joe OIiver, ODJB, etc,)
New Orleans styles (note plural styles)
Chicago/Austin High style
Swing styles (note plural)
Bebop
Hard bop/funk
Free styles/avant garde/"the new thing" (note plural styles)
Fusion styles (note plural)
And of course many many blends of these styles exist.
There are people currently working, playing, performing, and enjoying all of these styles of "jazz" music, as well as the related forms of African-American improvised music that are either directly derived from, or heavily influenced by, the form we call "jazz".
Far too many people have a grossly mistaken idea that jazz is limited to a very abstract, austere music with little melodic appeal to the lay person. This is NOT TRUE. Yes, the most avant-garde styles can be quite difficult for the new listener. But Jazz is not just Coltrane's "OM" and Cecil Taylor. It's also Fats Waller, Ben Webster, Louis Armstrong, Duke Ellington, Billie Holiday, Ella Fitzgerald, and Betty Carter singing "Baby it's Cold Outside" with Ray Charles.