I think that it's the websites you visit that have to 'use' HTML5. Or not. Your browser simply has to support sites that are written using HTML5 features.
When you say you deleted Java, I assume you mean that you deleted the Java run-time executable. That would mean that you could no longer run any sites that use Java applets. Not sure how many sites that would affect, but Java applets have been around for a long time, so presumably there are some. You might want to get the runtime executable back ..