A PDF is a metafile format, HTML is not. HTML isn't good with extended markup. Look how poorly some web building utilities code pages. Though, HTML was designed from SGML, which was for electronic publishing.
It won't be perfect, but thy this
Adobe Convert PDF to HTML Tool.
Formatting will not hold well, if at all, and all of the great features of metafiles will likely be lost. For instance you couldn't imbed and application, font, etc...
It was once possible to convert a PDF to Text using OS Xs printing menu, but heck if I see it anymore. Maybe it was a an app.
I don't know if Adobe Acrobat can save as an HTML file, but it seems it should.
At worst, you could convert the PDF to another graphic format and set that as the background for a web page. Otherwise, most browsers can access a PDF.
Why HTML? and How cool is this. I hope I am wrong. This would be a great tool.
[EDIT] I may stand corrected Rokem.