MIME type

To properly list the HTML5 application to the browser, the HTTP server needs to announce them as such. For this, a mime-type change is needed. This could be done globally, or locally using e.g. server side scripting such as PHP or ASP. 

Here are some examples, including some that do not require a new mimetype/file-extension to be added:

For Apache, globally in "mime.types".

Change "mime.types" and add the following statement:

text/html;charset="UTF-8"     html

 if you want to keep .html5 reserved, or

text/html;charset="UTF-8"     html