repalce some text in doc document using asp.net

Words in table as in html table in word, right? (not DB table!)

One of the ways:
Using Javascript & Work Macro

Since it's a Web application in consideration, what you are asking requires knowledge not only of Javascript but of the Microsoft Word Macro Language and ActiveX automation through which you can access the word application.

To learn more about the latter you need to learn about the Javascript "ActiveXObject" and "GetObject" and you need to look through the Microsoft Word help files for information on the Microsoft Word Object Model and automation. Full information on word's Macro language can be found in its help files.

To give you a starter, when your Word Document is open, you can get a handle on the Word automation object using:-

var oWord=GetObject("","Word.Application");
var oActiveDocument=oWord.ActiveDocument;

The rest of it you can find in MS Word's help files if you look for it.