FIX: The onbeforeunload event unexpectedly occurs when you view a Web page in Internet Explorer 6 on a computer where Windows XP Service Pack 2 or Windows Server 2003 Service Pack 1 is installed (905498)


The information in this article applies to:

  • Microsoft Internet Explorer 6.0, when used with:
    • Microsoft Windows XP Service Pack 2
    • Microsoft Windows Server 2003 SP1
Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry

SYMPTOMS

When you view a Web page in Microsoft Internet Explorer 6 on a computer where Microsoft Windows XP with Service Pack 2 (SP2) or Microsoft Windows Server 2003 with Service Pack 1 (SP1) is installed, the onbeforeunload event unexpectedly occurs.

This problem occurs when the Web page streams a file that has the "Content-disposition: attachment" header into an IFRAME element.

RESOLUTION

Windows XP

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.Registry informationWarning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

You must create a registry subkey or modify a registry subkey to enable this hotfix. To do this, follow these steps.

Note This hotfix was released together with security update 896688. If security update 896688 is installed, you do not have to create the registry subkey to enable this hotfix.
  1. Click Start, click Run, type regedit, and then click OK.
  2. Locate and then click the following registry subkey:

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl

  3. On the Edit menu, point to New, and then click Key.
  4. Type FEATURE_NO_ONBEFOREUNLOAD_EVENT_KB905498, and then press ENTER.
  5. Click FEATURE_NO_ONBEFOREUNLOAD_EVENT_KB905498.
  6. On the Edit menu, point to New, and then click DWORD Value.
  7. Type iexplore.exe, and then press ENTER.
  8. Click iexplore.exe.
  9. On the Edit menu, click Modify.
  10. Type 00000001, and then click OK.
  11. Exit Registry Editor.
File information The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
File nameFile versionFile sizeDateTimePlatformSP requirement
Mshtml.dll6.0.2900.27393,016,70416-Aug-200502:21x86SP2
Shdocvw.dll6.0.2900.27391,494,01616-Aug-200502:21x86SP2

Windows Server 2003

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows Server 2003 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.File information The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
File nameFile versionFile sizeDateTimePlatformSP requirement
Mshtml.dll6.0.3790.26773,152,38407-Apr-200603:54x86SP1
Shdocvw.dll6.0.3790.26791,513,47211-Apr-200608:01x86SP1

WORKAROUND

To work around this problem, use the onunload event. For more information about how to use the onunload event, visit the following Microsoft Developer Network (MSDN) Web site:

http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/reference/events/onunload.asp

STATUS

Microsoft has confirmed that this is a problem in Internet Explorer 6 for Windows XP Service Pack 2 and for Windows Server 2003 Service Pack 1.

MORE INFORMATION

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Modification Type:MinorLast Reviewed:7/26/2006
Keywords:kbQFE kbfix kbbug kbHotfixServer kbpubtypekc KB905498 kbAudDeveloper kbAudITPRO
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