You may experience slow performance when you view a Web page that uses JScript in Internet Explorer 6

When you use Microsoft Internet Explorer 6 to view a Web page that uses Microsoft JScript, you may experience slow performance.

This problem may occur when a script creates many variables at the same time. The problem may also occur when a script contains many unique values that are parsed at the same time. The problem occurs because of the way the JScript engine performs garbage collection.

The garbage collection algorithm monitors the following values:

• The number of variable allocations in the script
• The number of literal values that are used in the script
• The total size of the string values that are allocated in the script

When thresholds for these values are exceeded, garbage collection occurs. The garbage collection process interrupts scripts that are running. Therefore, the scripts are suspended until garbage collection is completed.

To resolve this problem, install Microsoft Windows Script 5.7. Windows Script 5.7 is available for the following operating systems.

Windows XP

Download the Windows Script 5.7 for Windows XP package now.

Windows Server 2003

Download the Windows Script 5.7 for Windows Server 2003 package now.

Windows 2000

Download the Windows Script 5.7 for Windows 2000 package now.

Hotfix information

Microsoft Windows XP

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

You must have Microsoft Windows XP Service Pack 2 (SP2) installed to apply this hotfix. If you need to install this update on Windows XP 64-bit Edition, install the Microsoft Windows 2003 x64 update on the x64 version on Windows XP.

Restart requirement

You must restart the computer after you apply this hotfix.

Registry information

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

This hotfix provides three registry configuration options that you can use to customize the frequency of garbage collection in JScript. These options can provide a more optimal user experience when you run scripts that use many variables, use many values, or allocate lots of strings.

After you apply this hotfix, follow these steps to configure these registry configuration options:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
3. On the Edit menu, point to New, and then click Key.
4. Type Windows Script, and then press ENTER.
5. Right-click Windows Script, click New, and then click Key.
6. Type Features, and then press ENTER.
7. Right-click Features, click New, and then click Key.
8. Type Iexplore, and then press ENTER.
   
   Note This registry entry sets JScript garbage collector options for Internet Explorer. You can add more registry entries to set JScript garbage collector options for other programs. In each entry, use the executable file name without the file name extension.
9. Right-click Iexplore, click New, and then click DWORD Value.
10. Type GcVarTrigger, and then press ENTER.
11. Right-click GcVarTrigger, and then click Modify.
12. In the Value data box, type a value to set the number of variables that can be allocated in JScript before garbage collection occurs, and then click OK.
    
    Note The default value is 0x00000100. We recommend an initial value of 0x00000500.
13. Right-click Iexplore, click New, and then click DWORD Value.
14. Type GcValTrigger, and then press ENTER.
15. Right-click GcValTrigger, and then click Modify.
16. In the Value data box, type a value to set the number of literal values that can be allocated in JScript before garbage collection occurs, and then click OK.
    
    Note The default value is 0x00001000. We recommend an initial value of 0x00005000.
17. Right-click Iexplore, click New, and then click DWORD Value.
18. Type GccbSysTrigger, and then press ENTER.
19. Right-click GccbSysTrigger, and then click Modify.
20. In the Value data box, type a value to set the number of string value space in bytes that can be allocated in JScript before garbage collection occurs. and then click OK.
    
    Note The default value is 0x00010000. We recommend an initial value of 0x00020000.
21. Exit Registry Editor, and then restart the computer.

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.

Microsoft Windows XP, 32-bit versionsMicrosoft Windows XP Professional x64 Edition

Windows Server 2003

Service pack information

To resolve this problem, obtain the latest service pack for Windows Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

You must have Windows Server 2003 Service Pack 1 (SP1) installed to apply this hotfix.

Restart requirement

You must restart the computer after you apply this hotfix.

Registry information

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

This hotfix provides three registry configuration options that you can use to customize the frequency of garbage collection in JScript. These options can provide a more optimal user experience when you run scripts that use many variables, use many values, or allocate lots of strings.

After you apply this hotfix, follow these steps to configure these registry configuration options:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
3. On the Edit menu, point to New, and then click Key.
4. Type Windows Script, and then press ENTER.
5. Right-click Windows Script, click New, and then click Key.
6. Type Features, and then press ENTER.
7. Right-click Features, click New, and then click Key.
8. Type Iexplore, and then press ENTER.
   
   Note This registry entry sets JScript garbage collector options for Internet Explorer. You can add more registry entries to set JScript garbage collector options for other programs. In each entry, use the executable file name without the file name extension.
9. Right-click Iexplore, click New, and then click DWORD Value.
10. Type GcVarTrigger, and then press ENTER.
11. Right-click GcVarTrigger, and then click Modify.
12. In the Value data box, type a value to set the number of variables that can be allocated in JScript before garbage collection occurs, and then click OK.
    
    Note The default value is 0x00000100. We recommend an initial value of 0x00000500.
13. Right-click Iexplore, click New, and then click DWORD Value.
14. Type GcValTrigger, and then press ENTER.
15. Right-click GcValTrigger, and then click Modify.
16. In the Value data box, type a value to set the number of literal values that can be allocated in JScript before garbage collection occurs, and then click OK.
    
    Note The default value is 0x00001000. We recommend an initial value of 0x00005000.
17. Right-click Iexplore, click New, and then click DWORD Value.
18. Type GccbSysTrigger, and then press ENTER.
19. Right-click GccbSysTrigger, and then click Modify.
20. In the Value data box, type a value to set the number of string value space in bytes that can be allocated in JScript before garbage collection occurs. and then click OK.
    
    Note The default value is 0x00010000. We recommend an initial value of 0x00020000.
21. Exit Registry Editor, and then restart the computer.

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.

Microsoft Windows Server 2003 with Service Pack 1Microsoft Windows Server 2003, x64-based versions

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Microsoft Windows Server 2003 Service Pack 2.

For more information about JScript, visit the following Microsoft Developer Network (MSDN) Web site: For more information about the terms that are used in this article, click the following article number to view the article in the Microsoft Knowledge Base:

Technical support for x64-based versions of Microsoft Windows

If your hardware came with a Microsoft Windows x64 edition already installed, your hardware manufacturer provides technical support and assistance for the Windows x64 edition. In this case, your hardware manufacturer provides support because a Windows x64 edition was included with your hardware. Your hardware manufacturer might have customized the Windows x64 edition installation by using unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with a Windows x64 edition. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware. If you purchased a Windows x64 edition such as a Microsoft Windows Server 2003 x64 edition separately, contact Microsoft for technical support.

For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site: For product information about x64-based versions of Microsoft Windows Server 2003, visit the following Microsoft Web site: