What are some multiplayer online games I can play without downloading?

My friends and I are looking for games we can play online without downloading. Games like Habbo, Runescape, Gaia, etc. Games like the first two are more preferrable. Games where we could walk, talk, etc.
I’m looking for multiplayer online games. It’s where I can play with my friends online, even though i’m at home and they’re at their own place.