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HttpCookie.HttpOnly 屬性

  • 參考

定義

命名空間:
System.Web
組件:
System.Web.dll

取得或設定數值，指定 Cookie 是否由用戶端指令碼存取。

public:
 property bool HttpOnly { bool get(); void set(bool value); };
public bool HttpOnly { get; set; }
member this.HttpOnly : bool with get, set
Public Property HttpOnly As Boolean

屬性值

Boolean

如果 Cookie 有 true 屬性且不可以透過用戶端指令碼存取，則為 HttpOnly，否則為 false。 預設為 false。

範例

下列程式碼範例示範如何撰寫 HttpOnly Cookie，並示範用戶端如何透過 ECMAScript 存取 Cookie。

<%@ Page Language="C#" %>


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
    void Page_Load(object sender, EventArgs e)
    {
        // Create a new HttpCookie.
        HttpCookie myHttpCookie = new HttpCookie("LastVisit", DateTime.Now.ToString());

        // By default, the HttpOnly property is set to false 
        // unless specified otherwise in configuration.

        myHttpCookie.Name = "MyHttpCookie";
        Response.AppendCookie(myHttpCookie);

        // Show the name of the cookie.
        Response.Write(myHttpCookie.Name);

        // Create an HttpOnly cookie.
        HttpCookie myHttpOnlyCookie = new HttpCookie("LastVisit", DateTime.Now.ToString());

        // Setting the HttpOnly value to true, makes
        // this cookie accessible only to ASP.NET.

        myHttpOnlyCookie.HttpOnly = true;
        myHttpOnlyCookie.Name = "MyHttpOnlyCookie";
        Response.AppendCookie(myHttpOnlyCookie);

        // Show the name of the HttpOnly cookie.
        Response.Write(myHttpOnlyCookie.Name);
    }
</script>


<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
<script type="text/javascript">
function getCookie(NameOfCookie)
{
    if (document.cookie.length > 0) 
{ 
    begin = document.cookie.indexOf(NameOfCookie+"="); 
    if (begin != -1)
   { 
    begin += NameOfCookie.length+1; 
      end = document.cookie.indexOf(";", begin);
      if (end == -1) end = document.cookie.length;
      return unescape(document.cookie.substring(begin, end));       
      } 
  }
return null;  
}
</script>

<script type="text/javascript">

    // This code returns the cookie name.
    alert("Getting HTTP Cookie");
    alert(getCookie("MyHttpCookie"));

    // Because the cookie is set to HttpOnly,
    // this returns null.
    alert("Getting HTTP Only Cookie");
    alert(getCookie("MyHttpOnlyCookie"));

</script> 


</body>
</html>

<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

  Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
    
    ' Create a new HttpCookie.
    Dim myHttpCookie As New HttpCookie("LastVisit", DateTime.Now.ToString())

    ' By default, the HttpOnly property is set to false 
    ' unless specified otherwise in configuration.

    myHttpCookie.Name = "MyHttpCookie"
    Response.AppendCookie(myHttpCookie)

    ' Show the name of the cookie.
    Response.Write(myHttpCookie.Name)

    ' Create an HttpOnly cookie.
    Dim myHttpOnlyCookie As New HttpCookie("LastVisit", DateTime.Now.ToString())

    ' Setting the HttpOnly value to true, makes
    ' this cookie accessible only to ASP.NET.

    myHttpOnlyCookie.HttpOnly = True
    myHttpOnlyCookie.Name = "MyHttpOnlyCookie"
    Response.AppendCookie(myHttpOnlyCookie)

    ' Show the name of the HttpOnly cookie.
    Response.Write(myHttpOnlyCookie.Name)

  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
<script type="text/javascript">
function getCookie(NameOfCookie)
{
  if (document.cookie.length > 0) 
  { 
    begin = document.cookie.indexOf(NameOfCookie+"="); 
    if (begin != -1)
    { 
    begin += NameOfCookie.length+1; 
      end = document.cookie.indexOf(";", begin);
      if (end == -1) end = document.cookie.length;
      return unescape(document.cookie.substring(begin, end));       
    } 
  }
  return null;  
}
</script>

<script type="text/javascript">

// This code returns the cookie name.
alert("Getting HTTP Cookie");
alert(getCookie("MyHttpCookie"));

// Because the cookie is set to HttpOnly,
// this returns null.
alert("Getting HTTP Only Cookie");
alert(getCookie("MyHttpOnlyCookie"));

</script> 

</body>
</html>

備註

Microsoft Internet Explorer 第 6 版 Service Pack 1 和更新版本支援 Cookie 屬性， HttpOnly 有助於減輕造成遭竊 Cookie 的跨網站腳本威脅。 遭竊的 Cookie 可以包含識別網站的敏感性資訊，例如 ASP.NET 會話識別碼或表單驗證票證，而且攻擊者可以重新執行，以便偽裝為使用者或取得敏感性資訊。 HttpOnly當符合規範的瀏覽器收到 Cookie 時，用戶端腳本無法存取。

警告

HttpOnly將 屬性設定為 true 不會防止具有網路通道存取權的攻擊者直接存取 Cookie。 請考慮使用安全通訊端層 (SSL) 來協助防範此情況。 工作站安全性也很重要，因為惡意使用者可以使用開啟的瀏覽器視窗或包含持續性 Cookie 的電腦，以取得具有合法使用者身分識別的網站存取權。

適用於