I think the rule says "Yes, you can make any changes to the project or project page during the rating period, just make sure that the original version of the game can still be downloaded if your project has a downloadable build and make a note on the game page describing what the changes in the post-jam version are." I think since you're game isn't downloadable, it's ok to just replace the web version. The only other requirement is to describe what the changes are.