Performance Considerations in Windows Internet Explorer

Note  As of December 2011, this topic has been archived and is no longer actively maintained. For more information, see Archived Content. For information, recommendations, and guidance regarding the current version of Windows Internet Explorer, see Internet Explorer Developer Center.

Developers who wish to gain more performance from Internet Explorer have many tips and techniques available.This page provides links and tips for getting extra performance from DHTML, Script, Web Servers, ActiveX Controls, Java Applets, and Plugins.

Enhancing DHTML and Script Performance


Building High Performance HTML Pages

Frequent Flyers: Boosting Performance on DHTML Pages

Asynchrony: Loved Your Performance

More Performance Tips

About Active Accessibility Support

Faster DHTML in 12 Steps


  • Using the userdata DHTML behavior to cache client data improves performance by reducing the need to query a server for client-specific information. For more information, see Introduction to Persistence.
  • Using the borderCollapse and tableLayout properties for tables significantly improves the performance of table rendering. For more information, see Enhancing Table Presentation.
  • A custom backdrop for the IE toolbar that is too small (for example, smaller than 10 by 10 pixels) can seriously degrade the performance of IE. For more information, see Customizing the Browser Toolbar.
  • Overall painting performance can be improved by setting the updateInterval property, although abnormally large or small values may decrease performance. For more information, see updateInterval.
  • Using the textOverflow property to render ellipses is an efficient alternative to building ellipses in DHTML. For more information, see textOverflow.
  • Use the literalContent attribute to make parsing of Element Behaviors more performant. For more information, see Using the literalContent Attribute.
  • Include an ID for the saveFavorite, saveHistory, and userdata Element behaviors to improve their performance. For more information, see saveFavorite.
  • Using atomic selection mode in a document will decrease performance whenever selections are made anywhere in the document. For more information, see ATOMICSELECTION
  • To improve performance, it is strongly recommended that you access CSS filters through the object model whenever possible, and only access the filter string when object model functionality is not adequate. For more information, see Introduction to Filters and Transitions.
  • It is important to consider performance when designing Web pages with visual filters. Processing time is required to calculate the display of filter effects, and some effects require more time than others to apply. For more information, see Introduction to Filters and Transitions.
  • For best performance with the RevealTrans filter, use the predefined optimized transition filters. For more information, see RevealTrans.
  • Because they are compiled, binary behaviors exhibit better performance than a script-based element behavior. For more information, see How to Create a Binary Element Behavior using ATL.
  • Using the defer property on the script object can improve the download performance of the page, as IE does not need to parse and execute the script and can continue downloading the parsing the page instead. For more information, see defer.
  • Setting the lightweight attribute to true on an HTML Component's Component element improves the performance for an HTML Component that does not contain markup. For more information, see PUBLIC:COMPONENT.

Enhancing Server Performance


Fiddler PowerToy - Part 2: HTTP Performance

Enhancing ActiveX Performance


  • ActiveX controls using IHTMLTxtRange::execCommand or IHTMLTxtRange::execCommandShowHelp can use IOleCommandTarget::Exec for better performance. For more information, see defer property.
  • ActiveX controls that are not apartment-model aware will suffer from degraded performance. For more information, see Building ActiveX Controls for Internet Explorer.
  • A windowless ActiveX control often performs better than a windowed control. For more information, see Building ActiveX Controls for Internet Explorer.