Tonight is the correct spelling.
You mean which one is proper?
Tonight is proper. They mean the same tonites usually just used as a shortcut
They both mean the exact same thing. "Tonight" is correct and proper. "Tonite" is just shortened and written slang. Just like "through" and "thru."
Tonite is great for the uneducated.
Tonight is great for the educated.
Tonihgt is great for the fast typist.
Ternight is great for termites.
Thenight is great for nightowls (night-owls).
Thisnight is great for Santa Claus.
Where do you fit in?
(US, nonstandard) (informal, entertainment industry) Alternative spelling of tonight.
Tonite is often used in advertising in the entertainment industry in the United States, for example on signs outside theaters displaying the evening's performances. Tonight is almost always used in most other contexts such as academia, politics, news media, etc.
An explosive compound; a preparation of gun cotton.