Slow web browser performance when you view a Web page that uses JScript in Internet Explorer 6

Consider the following scenario:

• You are running a Windows Server 2003-based computer or a Windows XP-based computer.
• You are running version 5.6 of Microsoft Windows Script.
• You use Internet Explorer 6 to view a Web page that uses Microsoft JScript.

In this scenario, you may experience slow Web browser performance.

This problem may occur if a script creates many variables at the same time. This problem may also occur when a script contains many unique values that are parsed at the same time. This problem occurs because of the way that 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, those running scripts are suspended until garbage collection is completed.

This hotfix package includes an improved JScript garbage collector. This improved garbage collector is included with Windows Script 5.7 and with Windows Vista. This new garbage collector can significantly improve the performance of applications that create many objects, such as Ajax-style Web applications. These performance improvements are now available to users of Windows Script 5.6. This hotfix provides improvements over hotfix 919237.

NOTE This issue is fixed in Internet Explorer 8.0. For more information, click the following article number to view the article in the Microsoft Knowledge Base: The following files are available for download from the Microsoft Download Center:

Windows XP, x86-based versions

Download the Windows XP hotfix package now.

Windows XP, x64-based versions

Download the Windows XP x64-based versions hotfix package now.

Windows Server 2003, x86-based versions

Download the Windows Server 2003 hotfix package now.

Windows Server, x64-based versions

Download the Windows Server 2003 x64-based versions hotfix package now. For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

Windows XP hotfix information

Prerequisites

To apply this hotfix, you must have Windows XP Service Pack 2 installed on the computer. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix replaces hotfix 917344 for Windows XP and Windows Server 2003.

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.

Windows XP with Service Pack 2

Windows XP, x64-based versions

Windows XP with Service Pack 2, x64-based versions

Windows Server 2003 hotfix information

Prerequisites

To apply this hotfix, you must have Windows Server 2003 Service Pack 1 or Windows Server 2003 Service Pack 2 installed on the computer. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix replaces the following security bulletin:

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.

Windows Server 2003 with Service Pack 1, x86-based versions

Windows Server 2003 with Service Pack 2, x86-based versions

Windows Server 2003, x64-based versions

Windows Server 2003 with Service Pack 2, x64-based versions

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about optimizing Internet Explorer, click the following article number to view the article in the Microsoft Knowledge Base: For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: To download and install Internet Explorer 8, visit the following Microsoft Web site: http://www.microsoft.com/windows/internet-explorer/