We've already blogged about common misconceptions about HTML5 games, including the misconception that "HTML5 games can't do fullscreen". In the r85 beta, released on Monday, we've added a new feature to help make fullscreen work even better with your HTML5 games: the Browser object can now request fullscreen from an in-page game. In other words, a game embedded in to a web page with other content around it can now switch in to full-monitor display! Previously this was only possible with the 'Fullscreen in browser' setting, which forced the game to take up the whole browser window, removing the opportunity to have other content on the page.
For a demo, try the fullscreen-enabled Ghost Shooter demo. Notice how the game is embedded to a page with other content, but if you press F, the game takes up the whole monitor. Note this is only currently supported in Firefox and Chrome - other browsers are yet to add fullscreen support.
This might seem like a minor tweak, but I think it's actually quite important to help engage players on the web. Often when surfing, people have short attention spans. However, if they find a game they like on their travels, it's probably annoying to have to play in a tiny rectangle in the corner of a huge monitor. There's also a whole page of hyperlinks and a screen full of tabs and other apps making it just one click to leave. Being able to switch the game in to full-monitor display will help them fully immerse in the game, without any distractions, and hopefully get them playing for longer too. And you're still only a bookmark away from a fullscreen gaming experience, which is unbeatable convenience compared to any other way to run a fullscreen game.
Don't forget that fullscreen mode will resize the window, so you'll need to add support for multiple screen sizes.
I think being able to do this is kind of cool, and hopefully will help end concern about being able to make fullscreen games on the web. Let's hope the other browser makers catch up with Firefox and Chrome soon!