Using .vob directly as a file format won't work in most cases on a web page. (I am weak in video but I know that to be true from playing with it before) If you look here:
http://www.afterdawn.com/glossary/terms/vob.cfm
pay special attention to:
"In order to view stand-alone VOB files, you need to have a DVD player software that supports VOB playback."
Without that installed on someones computer (and most people will not have that) You will see the download dialog box when the link is clicked on to go to the .vob file.
What you might want to look at is software that can convert that to Flash That will work in most cases for people viewing on the web.