Microsoft KB Archive/942840

= You may experience slow Web browser performance when you view a Web page that uses JScript in Internet Explorer 6 on a Windows Server 2003-based computer or on a Windows XP-based computer =

Article ID: 942840

Article Last Modified on 11/27/2007

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APPLIES TO


 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows Server 2003, Web Edition
 * Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
 * Microsoft Windows Server 2003, Standard x64 Edition
 * Microsoft Windows Server 2003, Enterprise x64 Edition
 * Microsoft Windows Server 2003, Datacenter x64 Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional x64 Edition

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SYMPTOMS
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.



CAUSE
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.



RESOLUTION
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. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

919237 You may experience slow performance when you view a Web page that uses JScript in Internet Explorer 6

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:

119591 How to obtain Microsoft support files from online services

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.

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:

322389 How to obtain the latest Windows XP service pack

Restart requirement
You must restart the computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

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.

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:

889100 How to obtain the latest service pack for Windows Server 2003

Restart requirement
You must restart the computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

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 2, x64-based versions


STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



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

Keywords: kbwinxppresp3fix kbwinserv2003postsp2fix kbexpertisebeginner kbbug kbfix kbqfe KB942840

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