You still haven't said what "all" those extensions are, but if you mean that literally, then browsers simply won't be able to do that. There's only a limited range of document formats that browsers (with or without plugins) know how to make sense of.
their intention is nobody can manipulate these document which is stored in our software.
I don't understand this. The original is in the DMS, it *can't* be changed by anything the user does, unless the DMS lets the user save changes back to the system. So the basic premise sounds a bit flawed to me.
we have to save the document in our own format.and at the time of retrival it should be open in our own viewer. i am not getting the way from where should i start to save the document and retreve the document in our own format.
OK, so what you're saying is that actually you do *not* have to open and display all those formats - you need to convert them into your own internal format, and then display that; is that correct? If that's the case, what step are you having difficulties with - converting several document formats to your internal format, or displaying the internal format? What do you have so far?