A handy tutorial on getting them working
"Recently while working on Blox I ran into some issues getting bitmap fonts to load and display properly in CocoonJS. I was originally using TrueType Fonts and had no issues loading them but no matter what font I chose the edges of each character were blurry when rendered. I decided to try converting the TTF into a bitmap font and loading them that way. The problem was, CocoonJS doesn’t have an XML parser so it couldn’t load the fonts."
"There’s some information scattered around various forum posts on how to bypass this by converting the XML into JSON but Google didn’t turn them up right away, so I decided to consolidate all of the steps that I took to get it working here in one place (that is hopefully easier to find). And, best of all, my fonts are now sharp and clear!"