As others said.
They are totally different and Javascript is not suited to anythign of any great compelxity.
To be perfectly honest, if you have to ask this queation you are SO far away from writing a MMOLRPG it isnt funny. These are the hardest games to write, taking thelargest bodies of knowledge over the most areas.
My suggestions:
(1) Go hang around our “Newless Clubies” area. Read all the advice given to other new programmers there regularly.
(2) Oure first pecie of adviceto all newbies: chose a VERY simple starting project. A classic game like Pac Man or Space Invaders is a good starting point,