GameMaker HTML5 Player

(The below information is out of date.)
GameMaker HTML5 Player (GHP) is a free way to convert and play GameMaker games in a web browser.
The converter is still under construction and can convert basic pieces of code.
The player is still being actively improved, but is quite capable. You can find the testing version here.
If you know Java or Javascript, feel free to contribute to our GitHub.