Voidwars

From VoidWiki

Voidwars is a free multiplayer online strategy game. You must join forces with friends to crush enemy alliances using fleets of ships. Manage your empire correctly and rule the universe! [...] Set in a region of space known as the "void", you must expand from your colonised world and fight for control of the many planets and anomalies. - http://www.voidwars.com

You've just read the official game description written by the developers, and it doesn't even come close to it. Voidwars will remind some players of famous PC games like Birth of the Federation or Master of Orion with their combination of strategic and tactical features on an elaborate 2D map containing static and moveable elements like refueling stations and assault fleets. It is written in PHP and Javascript and can be played from any computer using a web browser (working browsers: Firefox and Mozilla/Epiphany, Internet Explorer is known to cause some problems). A Voidwars round currently contains 64 players and lasts several months.