function LinkKeyword(bIgnoreCase, MainStr, sNeedReplace, sReplaceWith)
dim sResult
Dim objRegExp
Set objRegExp = New Regexp
objRegExp.IgnoreCase = bIgnoreCase
objRegExp.Global = True
objRegExp.Pattern = "\b" & sNeedReplace & "\b(?![\w ]*</a>|>)"
sResult = objRegExp.Replace(MainStr, sReplaceWith)
Set objRegExp = Nothing
LinkKeyword = sResult
end function