Build a simple webpage that looks like youtube with a chat function. Easy work check the description

I have a film project that requires me to film a computer on a youtube page. The script calls for the youtube page to have a chat function that does not exist on youtube and I need to be able to edit all of the elements of the page. Please look at the page linked for an example. [login to view URL] The page needs to look just like youtube with the youtube logo and all of the other items on the page. None of the features need to work other than the ability for me to embed the video I want to play and the chat feature I will describe. I want clean html and placeholder graphics so I can make the page look right for each shot. I am comfortable editing the html so you dont need any type of CMS. Chat feature on the page. I need a chat box to pop up on the bottom of the page. It should look similar to facebook chat when you are on facebook in a web browser. A little window popping up from the bottom of the page. This page will not be used by real end users and is only for filming so it doesn't have to have an authentication system. Simple is better. But I do need avatars. Its 1 on 1 chat that doesn't need to be persistent and can be lost if the page refreshes. I'll leave the engineering up to you. I just need a way to have chat pop up while the page is being viewed then some bank and forth chatting needs to happen.