因为所输入的参数类型不同，所以判断的方法也不一样。如何正确的判断参数是否为空？
具体的请看下文所示：
<%
'Check a variable isn't "empty"
Function IsBlank(ByRef TempVar)
'by default, assume it's not blank
IsBlank = False
'now check by variable type
Select Case VarType(TempVar)
'Empty & Null
Case 0, 1
IsBlank = True
'String
Case 8
If Len(TempVar) = 0 Then
IsBlank = True
End If
'Object
Case 9
tmpType = TypeName(TempVar)
If (tmpType = "Nothing") Or (tmpType = "Empty") Then
IsBlank = True
End If
'Array
Case 8192, 8204, 8209
'does it have at least one element?
If UBound(TempVar) = -1 Then
IsBlank = True
End If
End Select
End Function
%>
Example Usage
<%
If IsBlank(Session("username"))Then
response.redirect("LoginFail.htm")
End If
%>
