for that you have to read the text file, locate the search string and process it.

Dim fso, f
Set fso = CreateObject("Scripting.FileSystemObject")
Set f = fso.OpenTextFile("HTMLfile.txt", 1, True)
Do While f.AtEndOfLine <> True
SearchString =a.readline 'you can also use readAll ..depends upon the requirement
SearchChar = "Keyword"
MyPos = Instr(1, SearchString, SearchChar)
'so you will get the location of you string you may use String functions like LEFT/RIGHT/MID to get what you want