'------------------------------
' 判断一个串是否是域名
'------------------------------
function IsDomain( str )
	'On error resume next

	Dim Letters, i, c, L
	Letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890-:/.@~?#$%^&*()_=\|{}[];/"
	Str = Trim(str)
	L = Len(str)
	If L = 0 Then
		IsDomain = False
		Exit Function
	ElseIf L > 100 Then
		IsDomain = False
		Exit Function
	End If
	For i = 1 To L
		c = Mid(str, i, 1)
		If InStr(Letters, c) = 0 Then
			IsDomain = False
			Exit Function
		End If
	Next
	if InStr( str, "." ) = 0 then
		IsDomain = False
		Exit Function
	end If
	If left( str, 1 ) = "." or right( str, 1 ) = "." Then
		IsDomain = False
		Exit Function
	end if

	IsDomain = true

	if err then
		IsDomain = false
		err.clear
	end if
end function