VBScript のプロパティ、Pattern プロパティ \

everyday VBScript 
Set r = New RegExp

str = "abc" & vbCRLF & "abc"
r.Pattern = "\na"
Set Matches = r.Execute(str)
MsgBox Matches(0).FirstIndex ' 4

str = "abc\abc"
r.Pattern = "\\a"
Set Matches = r.Execute(str)
MsgBox Matches(0).FirstIndex ' 3

str = "a(b)c"
r.Pattern = "\(.\)"
Set Matches = r.Execute(str)
MsgBox Matches(0) ' (b)