Symptoms
When connecting to a published application using Secure Gateway or Web Interface, the following error message is received:
“Proxy detection failure: No JavaScript support.”
A JavaScript PAC file is being used for a proxy URL and the client Internet Explorer has “Use Automatic configuration script” configured.
Cause
An anti-virus program may block the execution of Jscript files. Another cause may be missing or incomplete registry values.
Resolution
1. Verify that the original JSCRIPT.DLL is still located in %systemroot%\system32.
2. Verify that the JSCRIPT.DLL is properly associated with JSFile.
To do that, run this command from a command line:
cd %systemroot%\system32
regsvr32 jscript.dll
3. As a test, give the user “Power User” rights or better > make the connection > then remove the elevated rights. The user, with normal rights, should then make the connection.
4. Use a Registry Monitor Tool to verify the CLSID (F414C260-6AC0-11CF-B6D1-00AA00BBBB58) associated with the JSFile extension (normally jscript.dll) and investigate and repair any “access denied” or the failure to create registry values.
In addition, verify the following keys exist and that the user has the correct access rights on them
"\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ProxySup.ProxySupMain.1
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ProxySup.ProxySupMain.1]
@="ProxySupMain"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ProxySup.ProxySupMain.1\CLSID]
@="{666006C6-C743-11D5-BA02-00C04F2EFC0F}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ProxySup.ProxySupMain.1\Insertable]"
5. Verify if the anti-virus program offers an option that would allow for the defining of exceptions to permit the execution of the required PAC script URL.
6. Ensure that you are using the most recent Citrix ICA Client, which can be downloaded in the download section of www.citrix.com.
Note: The ICA Client expects to find the correct proxy settings in the client workstations registry. The Auto proxy configuration steps for the 32-bit Windows ICA Client are as follows:
a. Automatic proxy detection is triggered when ProxyType=Auto is found in the ICA file or Appsrv.ini.
b. The Win32 ICA Client reads the registry value HKEY_CLASSES_ROOT\.htm to determine the workstation’s default browser. This value can be observed by typing assoc .htm at a command prompt. The value will be htmlfile if Internet Explorer is the default browser or MozillaHTML if Netscape is the default browser.
c. The Proxy settings for the default browser are read from the registry or the user’s profile:
1. For Internet Explorer, proxy settings are stored in the registry under
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyServer
2. For Netscape, proxy settings are stored in the user’s profile under
Application Data\Mozilla\Profiles\default in a file named prefs.js.
a. If the Web browser proxy settings point to a PAC script, the Win32 ICA Client performs a HTTP request to download the PAC script, then invokes the native Microsoft Windows JScript interpreter to parse the script. This step requires JScript support to be enabled in Windows and relies on JSCRIPT.DLL.
b. If “Automatically detect settings” is enabled in Internet Explorer, this setting is ignored and the Win32 ICA Client attempts a direct connection.
Note: Using an “.ins” file to dynamically configure all the browser settings, including the proxy address or the Auto configuration script URL setting, is a feature that is currently unique to Internet Explorer. Functionality that supports this was added to the Win32 ICA Client 8.100.
