web browser game

Hello peeps ! My project is a web based (MMO) game. It will be very similar with Travian, DarkThrone, Tribes, etc but it will also include some elements of RPG like Duels for example. First of all i want to know if the entire source code can be written in html, or do i need something else too, like ... i don't know - C++ ? Actually i am looking more for a partner, so if anyone thinks it has the time for it, we will discuss it in a more detailed matter. Hope to get my answer from you peeps. Thanks in advance, Take care !