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Software and platforms

Internet Explorer

Summary

Internet Explorer was the web browser Microsoft built into Windows from 1995, with versions for the Macintosh and Unix along the way. It began as a licensed version of Spyglass Mosaic, first released in August 1995 in a paid add-on pack for Windows 95, introduced ActiveX controls, the first commercial CSS support and the XMLHTTP object behind Ajax, and stayed the most-used browser until May 2012. Microsoft retired the Internet Explorer 11 desktop app on June 15, 2022, and supports an IE mode in Edge through at least 2029.

Web Building Encyclopedia · Software and platforms · Last reviewed October 22, 2026 · 8 min read

What Internet Explorer was

Internet Explorer, often shortened to IE, was the web browser Microsoft offered for Windows from 1995 until the browser’s retirement in 2022.12

It started from licensed code. Spyglass, which held the commercial rights to NCSA Mosaic, described Internet Explorer as a browser based on Spyglass Mosaic.1

Over eleven major versions it brought several technologies to the web, among them ActiveX controls, the first commercial support for CSS, the Trident rendering engine, and XMLHTTP, the object behind Ajax web applications.345

Internet Explorer overtook Netscape Navigator in the late 1990s and stayed the most-used browser until Google Chrome passed it in May 2012, by StatCounter’s count.67

That contest, and the U.S. antitrust case it led to, are covered in the entry on the browser wars. This entry follows the product.

Origins: Spyglass Mosaic and Windows 95 (1994 to 1995)

Spyglass signed an agreement with the University of Illinois in May 1994 for commercial rights to NCSA Mosaic. It then licensed its own version, Spyglass Mosaic, to Microsoft under an agreement dated December 12, 1994.1

The license was worldwide and paid per copy, with some fixed-fee terms. Until December 31, 1998, it allowed Microsoft to distribute the browser only as part of other Microsoft products.1

Microsoft began distributing Internet Explorer as part of Windows 95 in August 1995, Spyglass reported.1 Version 1.0 first came out on August 16, 1995 in Microsoft’s Plus pack, a paid add-on for Windows 95, rather than in the standard Windows 95 package.8 The trial court in United States v. Microsoft put the introduction in July 1995, and Dave Raggett’s history of HTML, published by the W3C, says version 1.0 was announced in August 1995.910

The court found the first version demonstrably inferior to Netscape’s browser of the time.9

Microsoft’s investment grew quickly. The court found that it spent more than $100 million a year on Internet Explorer from 1995, and that the team grew from five or six developers in early 1995 to more than a thousand in 1999.9

Internet Explorer 2.0 arrived in November 1995 for Windows NT and Windows 95, and versions for the Macintosh and Windows 3.1 followed in April 1996.10

Versions 3 and 4: ActiveX, CSS and Trident (1996 to 1998)

ActiveX

On March 12, 1996, Microsoft announced ActiveX, its framework for building interactive content from software components. “ActiveX Controls are small, fast, full-featured components for the Internet, intranets, and the desktop,” the announcement said.3

ActiveX Controls, previously called OLE Controls, could be embedded directly in HTML pages. Microsoft’s example was ActiveMovie, which let Internet Explorer 3.0 users play video inside the browser.3

Raggett notes that ActiveX made Microsoft’s browser unique, and that a plug-in called Ncompass was developed so Netscape’s browser could handle it.10

Internet Explorer 3.0

The 3.0 beta of May 29, 1996, added ActiveX controls, native support for VBScript and JavaScript, and HTML 3.2 features including borderless and floating frames, style sheets and tables.11

Microsoft’s version of JavaScript was called JScript. Work on it began in October 1995, when Robert Welland joined the Internet Explorer team.12

Matching Netscape’s behavior took effort. In Netscape’s browser, frames on one page shared their script objects, while Internet Explorer had built frames as isolated environments, which needed significant reengineering to match.12

Internet Explorer 3.0 launched on August 13, 1996, as a free download. Microsoft claimed it was the only browser supporting the latest HTML 3.2 and Cascading Style Sheets specifications, and that more than 1,000 ActiveX controls were available.13

More than 2,500 internet service providers distributed it besides the large online services, and Microsoft planned versions for the Macintosh, Unix and Windows 3.1 by the end of 1996.13

The W3C’s history of CSS confirms Internet Explorer 3 as the first commercial browser to support CSS. It handled most color, background, font and text properties reliably but implemented little of the box model, the rules for sizing and spacing boxes on a page.4

The trial court found that reviewers praised version 3.0’s vastly improved quality.9 Microsoft also invented tags of its own, Raggett notes, among them MARQUEE, which made text move across the screen.10 Today’s HTML standard lists marquee as obsolete and points to CSS animations instead.14

Internet Explorer 4.0 and Trident

Microsoft announced worldwide availability of Internet Explorer 4.0 on October 1, 1997, after a launch event in San Francisco the evening before. It came as browser-only, standard and full downloads, free online or on a CD-ROM for $4.95, in eight languages.15

Version 4.0 added Outlook Express for email, an Active Desktop that could show live content on the Windows desktop, and subscription Active Channels.15 In September 1997 Microsoft also introduced scriptlets, which let web authors build reusable objects with what it called Dynamic HTML.16

Version 4 replaced the display engine with one called Trident, the W3C’s CSS history says, removing many of version 3’s limits but adding bugs of its own.4 A rendering engine is the part of a browser that turns HTML and CSS into the page on screen.

Pressure over standards grew. In November 1998 the Web Standards Project published “IE’s Top 10 CSS Problems.”4

By the court’s figures, Internet Explorer’s share of browser usage rose from about 5% in early 1996 to around 50% by late summer 1998.6 Microsoft included the whole browser in Windows 98 at no extra charge.9

Versions 5 and 6: XMLHTTP and a long pause (1999 to 2006)

Internet Explorer 5 was released on March 18, 1999. Microsoft listed support for XML 1.0, XSL, HTML 4.0, CSS 1.0 and 2.0, and the Document Object Model, the interface that lets scripts read and change a page.17

Microsoft said it would deliver versions for Windows 98, 95, NT 3.51 and NT 4.0, Windows 3.1, Sun Solaris and HP-UX, with more than 26 languages rolling out over the following weeks.17 Microsoft claimed it rendered top sites up to 60% faster than Netscape Navigator 4.5.17

Version 5 also introduced XMLHTTP, as an ActiveX control. Microsoft later called the object the cornerstone of Ajax web applications, and noted that other browsers had implemented it over time.5 Ajax is a technique in which a page fetches new content from the server in the background and updates only the parts that changed, without a full reload.18

Other browsers offered it as a native XMLHttpRequest object. Internet Explorer 7 added that native version while keeping the ActiveX control, so older pages did not need rewriting.5

Internet Explorer 6 was posted for download on August 27, 2001, ahead of Windows XP, of which it was a core part. It also ran on Windows 98, Me, NT 4.0 and 2000, but not Windows 95.19

The next major version did not arrive until October 2006, more than five years later.1920 Meanwhile the Macintosh version, which the W3C describes as having better CSS support than the Windows one, lost Microsoft’s support in 2003.4

Versions 7 to 11: tabs and standards (2006 to 2013)

Internet Explorer 7 was released for Windows XP on October 18, 2006, with tabbed browsing, a Quick Tabs view of all open tabs, and new protections against malicious software and phishing.20

It was free to genuine Windows customers and was delivered as a high-priority automatic update from November 2006.20

Internet Explorer 8 followed on March 19, 2009. Microsoft called it its most standards-compliant browser to date and said it passed more W3C CSS 2.1 test cases than any other shipping browser.21

Microsoft had also contributed more than 7,000 CSS 2.1 test cases to the W3C in the previous year. Version 8 opened pages in standards mode by default, kept a Compatibility View list for older sites, and built in developer tools for HTML, CSS and JavaScript.21

Microsoft set the release of Internet Explorer 9 for March 14, 2011. It used the computer’s graphics processor to speed up HTML5 audio and video and introduced a new JavaScript engine, Chakra.22 It also combined the address and search boxes into one and added tab isolation with automatic recovery from crashes and hangs.22

Microsoft’s lifecycle records start support for Internet Explorer 10 on October 30, 2012, and for Internet Explorer 11, the last version, on November 13, 2013.2324

From January 12, 2016, Microsoft supported only the most current version of Internet Explorer available for each supported operating system. On Windows 7 SP1 and Windows 8.1, that meant Internet Explorer 11.25

Retirement (2021 to 2023)

On May 19, 2021, Microsoft announced that the Internet Explorer 11 desktop app would be retired on June 15, 2022, on certain versions of Windows 10, and pointed users to Microsoft Edge with its IE mode for older sites.26

The retirement went ahead on that date. Windows 11 had already removed Internet Explorer, and over the following months opening it on affected Windows 10 systems sent users to Edge.2

Microsoft’s post that day said the browser had served the web for more than 25 years. Some supported systems kept it, including Windows 10 LTSC, Windows Server, and Windows 8.1 and 7 with Extended Security Updates.2

Microsoft scheduled a Microsoft Edge update to disable the desktop app permanently on certain Windows 10 versions on February 14, 2023, and its retirement post now says the app has been permanently disabled.242 Microsoft has committed to supporting IE mode in Edge through at least 2029 and to giving at least one year’s notice before it ends.27

Internet Explorer no longer appears among the browsers StatCounter lists for desktop use worldwide. In September 2026 that list ran from Chrome at 65.09% to Brave at 1.12%.28

Timeline

  1. Edge update scheduled to permanently disable the IE11 desktop app on certain Windows 10 versions24
  2. Microsoft retires the Internet Explorer 11 desktop app2
  3. Microsoft announces the retirement date26
  4. Only the newest IE for each Windows version stays supported25
  5. Support begins for Internet Explorer 11, the last version24
  6. Support begins for Internet Explorer 1023
  7. Scheduled release of Internet Explorer 9, with the Chakra JavaScript engine22
  8. Internet Explorer 8 released, standards mode by default21
  9. Internet Explorer 7 adds tabbed browsing20
  10. Internet Explorer 6 posted for download ahead of Windows XP19
  11. Internet Explorer 5 released; XMLHTTP arrives as an ActiveX control17
  12. Internet Explorer 4.0 available worldwide, with the Trident engine15
  13. Internet Explorer 3.0 launches with early CSS support and ActiveX13
  14. Microsoft announces ActiveX3
  15. Internet Explorer 1.0 is released in Microsoft's Plus add-on pack for Windows 958

What it means for your website

Internet Explorer shaped how sites were built for more than 20 years. Its retirement simplifies things for most small businesses.

  • Drop Internet Explorer support on public sites. Microsoft retired the desktop app on June 15, 2022, and scheduled an Edge update to disable it permanently on certain Windows 10 versions on February 14, 2023.224 Workarounds written only for Internet Explorer can come out of your theme or templates.
  • Know the exception. Older company intranets and business applications may still run in Edge’s IE mode, which Microsoft supports through at least 2029.27 If a supplier’s portal works only there, ask the supplier for its migration date.
  • Retire ActiveX, MARQUEE and other IE-era pieces. A page that asks visitors to install an ActiveX control was built for a browser Microsoft no longer supports.32 The HTML standard lists marquee as obsolete in favor of CSS animations.14
  • Use a standard doctype. Browsers still keep a quirks mode that imitates Navigator 4 and Internet Explorer 5 for pages without one. Starting each page with <!doctype html> avoids it.29
  • Decide whether to update or rebuild. If your site still shows “best viewed in Internet Explorer” notices or depends on old plugins, our redesign guide explains how to choose between an update and a rebuild, and the redesign checklist lists what to save first.

See also

References

  1. Spyglass, Inc., Form 10-K for the fiscal year ended September 30, 1996. U.S. Securities and Exchange Commission (EDGAR). 1996-12. accessed October 22, 2026.
  2. Internet Explorer 11 has retired and is officially out of support: what you need to know. Microsoft Windows Experience Blog. 2022-06-15. accessed October 22, 2026.
  3. Microsoft Announces ActiveX Technologies. Microsoft. 1996-03-12. accessed October 22, 2026.
  4. A brief history of CSS until 2016. W3C. accessed October 22, 2026.
  5. Native XMLHTTPRequest object (Sunava Dutta, IEBlog). Microsoft. 2006-01-23. accessed October 22, 2026.
  6. United States v. Microsoft, Findings of Fact, section V.H (paragraphs 360 to 377). U.S. Department of Justice. 1999-11-05. accessed October 22, 2026.
  7. Independent web analytics firm StatCounter confirms milestone as Chrome overtakes IE globally for first calendar month. StatCounter. 2012-06-01. accessed October 22, 2026.
  8. Internet Explorer 1.0 (1995). Web Design Museum. accessed October 22, 2026.
  9. United States v. Microsoft, Court's Findings of Fact. U.S. Department of Justice. 1999-11-05. accessed October 22, 2026.
  10. A history of HTML (chapter 2 of Raggett on HTML 4). W3C. 1998. accessed October 22, 2026.
  11. Microsoft Internet Explorer 3.0 Beta Now Available. Microsoft. 1996-05-29. accessed October 22, 2026.
  12. JavaScript: The First 20 Years (Allen Wirfs-Brock and Brendan Eich), Proc. ACM Program. Lang. 4, HOPL, Article 77. Association for Computing Machinery. 2020-06. accessed October 22, 2026.
  13. Microsoft Launches Microsoft Internet Explorer 3.0 With Exclusive, Free Content Offers From Top Web Sites. Microsoft. 1996-08-13. accessed October 22, 2026.
  14. HTML Living Standard, section 16: Obsolete features. WHATWG. accessed October 22, 2026.
  15. Microsoft Internet Explorer 4.0 Now Available; Delivers "The Web the Way You Want It" to Users Worldwide. Microsoft. 1997-10-01. accessed October 22, 2026.
  16. Microsoft Introduces Scriptlets in Microsoft Internet Explorer 4.0, Enabling Reusable Dynamic HTML Components for the First Time. Microsoft. 1997-09-15. accessed October 22, 2026.
  17. Microsoft Delivers World's Fastest Modern Browser Available Today. Microsoft. 1999-03-18. accessed October 22, 2026.
  18. Ajax (glossary). MDN Web Docs. accessed October 22, 2026.
  19. IE 6 Posted to the Web (Scott Bekker). Redmond Magazine. 2001-08-28. accessed October 22, 2026.
  20. Microsoft Releases Windows Internet Explorer 7 for Windows XP. Microsoft. 2006-10-18. accessed October 22, 2026.
  21. Availability of Windows Internet Explorer 8 Brings New Opportunities for Web Developers. Microsoft. 2009-03-19. accessed October 22, 2026.
  22. IE9 Goes Final (Michael Desmond). Visual Studio Magazine. 2011-03-10. accessed October 22, 2026.
  23. Internet Explorer 10 (lifecycle). Microsoft Learn. accessed October 22, 2026.
  24. Internet Explorer 11 (lifecycle). Microsoft Learn. accessed October 22, 2026.
  25. Internet Explorer and .NET Framework 4.x support announcements. Microsoft Learn. accessed October 22, 2026.
  26. The future of Internet Explorer on Windows 10 is in Microsoft Edge. Microsoft Windows Experience Blog. 2021-05-19. accessed October 22, 2026.
  27. Lifecycle FAQ: Internet Explorer and Microsoft Edge. Microsoft Learn. accessed October 22, 2026.
  28. Desktop Browser Market Share Worldwide (September 2026). StatCounter Global Stats. 2026-09. accessed October 22, 2026.
  29. Quirks mode and standards mode. MDN Web Docs. accessed October 22, 2026.

Web Building Encyclopedia. First published October 22, 2026. Last reviewed October 22, 2026. Every fact on this page is linked to a source we opened. Spotted an error? Write to [email protected].