in reply to Need Help for Convert PDF to HTML
Your problem is that PDF is a page description language which, when executed by the printer, generates the desired graphics as its output. HTML, too, is a page description language. Neither of these has predictable semantic meaning. Thus, there is no (AFAIK) generalized solution to your quest.
On the other hand, maybe we can think outside the box here. If you can get to a source-document that is in an XML format, e.g. DocBook™, it is a simple matter to convert that either into PDF or HTML or both. So, is it possible for you to get your hands on such an (XML...) root document? That is to say, the source that the PDF you’re looking at came from? Many producers of technical documentation use content-management systems that are XML-based, and maybe, if you ask them very nicely, they’ll let you have a copy of the document in that format. Then, your objective would become quite trivial to achieve.
Basically... if you sallied down the primrose path of trying to extract data from a PDF, you probably will never arrive anywhere useful no matter how hard you bang your head. But if this is indeed a serious business requirement, there is a reasonable chance that there is another way to get at that information...