H.264 codecs create MP4s. MP4s that include certain other features are called AVC files.
I'm just not clear what you're trying to do. You're laying out a web page, right? If so, you create the frame in HTML and drop the MP4 into it. As long as the people viewing your web site have a media player on their computer that can play MP4s, they'll be able to watch the video.
If that's not it, you're going to have to be a bit more detailed in what you're looking for.
Are programming a web page with raw HTML or are you using a program like Dreamweaver to do it?