Hosting a game on dropbox

I have made a simple game for webplayer and built it to a “Game.html” and “Game.unity3d”, but when I uploaded them to a folder on my dropbox and shared the link to the Game.html file I only give me the option to download it. Why is it not working?

You need to use a public folder. On old Dropbox accounts (I.e. >2yrs ago or so), this was enabled by default. About a year ago you could still enable a public folder, though it was somewhat hidden. I believe new Dropbox accounts may not have this feature at all.