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HttpCapabilitiesBase.RequiresUniqueFilePathSuffix Property

Gets a value indicating whether the browser requires unique form-action URLs.

Namespace:  System.Web.Configuration
Assembly:  System.Web (in System.Web.dll)

public virtual bool RequiresUniqueFilePathSuffix { get; }

Property Value

Type: System.Boolean
true if the browser requires unique form-action URLs; otherwise, false. The default is false.

A self-referring HTML <form> element is one for which the action attribute specifies its own URL. If true, self-referring forms do not return the correct results. This is due to caching by either the browser or an intermediate gateway. To correct this, server control adapters append a default query string (__ufps=uniquefilepathsuffix) onto the form-action URL values of self-referring forms.

The following code example shows how to determine whether the browser requires unique form-action URLs.

<%@ page language="C#"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<script runat="server">
    void Page_Load(Object Sender, EventArgs e)

    void CheckBrowserCaps()
        String labelText = "";
        System.Web.HttpBrowserCapabilities myBrowserCaps = Request.Browser;
        if (((System.Web.Configuration.HttpCapabilitiesBase)myBrowserCaps).RequiresUniqueFilePathSuffix)
            labelText = "Browser requires FORM ACTION URLs be unique.";
            labelText = "Browser does not require FORM ACTION URLs be unique.";

        Label1.Text = labelText;

<html xmlns="" >
    <title>Browser Capabilities Sample</title>
    <form runat="server" id="form1">
            Browser Capabilities:
            <p/><asp:Label ID="Label1" Runat="server" />

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.