Function condition1() As Boolean
    Response.Write("condition1")
    Return False
End Function

Function condition2() As Boolean
    Response.Write("condition2")
    Return True
End Function

If condition1() And condition2() Then
    Response.Write("success")
Else
    Response.Write("fail")
End If
'结果：condition1 condition2 fail

private bool condition1()
{
    Response.Write("condition1");
    return false;
}

private bool condition2()
{
    Response.Write("condition2");
    return true;
}

if (condition1() && condition2())
    Response.Write("success");
else
    Response.Write("fail");
//结果：condition1 fail

'当cookie不存在时，程序出错：未将对象引用设置到对象的实例。
If Not (Request.Cookies("url") Is Nothing) And Request.Cookies("url").Value = "www.mzwu.com" Then
    'code ...
End If

If Not (Request.Cookies("url") Is Nothing) Then
    If Request.Cookies("url").Value = "www.mzwu.com" Then
        'code ...
    End If
End If

if (Request.Cookies["url"] != null && Request.Cookies["url"].Value == "www.mzwu.com")
{
    //code...
}