Free, non-downloadable, action rpgs

Most of these you are probably familiar with, since they are quite widespread, but these are some that I know about.

All battleon games are free and fun to play.
Adventurequest
Aqworlds
Mechquest
Dragonfable
Runescape
Some more that you may not be familiar with.

Tanoth-Free Rpg based on combat with other players to make gold for armor, weapons, and horses, dragons, etc. Go on adventures and work for money to get better equipment.

Gods of time- In this game you can chat with other players, fight other players and npc's, build fortresses to attack other players guilds and the ability to make your own guild, earn money for hundreds of items, weapons, and armor.

Tanoth-This is more of a laid back game since most of the time you will be earning rewards, while not even playing the game. You can work for up to 8 hours at a time (higher the level you are the better the rewards), you can go on adventures, which are usually around 30 minutes long, fight other players instantly, but only up to 10 every 15 minutes, buy a means of transportation (dragons, horses, donkey, etc.) in the stables to make work and adventures quicker, and buy thousands of weapons and armor of your choice.

Legend legacy of the dragons- Explore a very large world with the choice of being a human or a magmar(the rival's of the humans) and fight in tournaments against other players for fame and money. Take on many quests (all suitable for your level at the time), chat amongst many online players, including sending messages and gold to your offline buddies, gain new armor and weapons for better success in combat, increase skill capabilities including healing other players, and doing extra damage etc. Mine for crystals, sell them, or use them to upgrade equipment, battle alongside people of your own race, or travel far and fight against your rivals, which in each fight an unlimited amount of players can join making it somewhat unfair, but extremely intense, sometimes as far as 45 or so players against 5 on opposing teams.

These games are kinda alike and if you like one you will probably like the others as well,

Bitefight
Battleknight
Dragon Wars
Duels
Vampires