Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated IE or MSIE) is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995.

The first version of Internet Explorer, made its debut on August 24, 1995. It was a reworked version of Spyglass Mosaic, which Microsoft licensed from Spyglass Inc., like many other companies initiating browser development. It was first released as part of the add-on package Plus! for Windows 95 that year. Later versions were available as free downloads, or in service packs, and included in the OEM service releases of Windows 95 and later versions of Windows.

Originally Internet Explorer only ran on Windows using an Intel compatible (x86) processor. Current versions also run on x64, 32-bit ARMv7, PowerPC and IA-64. Versions on Windows have supported MIPS, Alpha AXP and 16-bit and 32-bit x86 but currently support only 32-bit or 64-bit. A version exists for Xbox 360 called Internet Explorer for Xbox using PowerPC and an embedded OEM version called Pocket Internet Explorer, later rebranded Internet Explorer Mobile, which is currently based on Internet Explorer 9 and made for Windows Phone using ARMv7, Windows CE, and previously, based on Internet Explorer 7 for Windows Mobile. It remains in development alongside the desktop versions.

Internet Explorer has supported other operating systems with Internet Explorer for Mac (using Motorola 68020+, PowerPC) and Internet Explorer for UNIX (Solaris using SPARC and HP-UX using PA-RISC), which have been discontinued.

Since its first release, Microsoft has added features and technologies such as basic table display (in version 1.5); XMLHttpRequest (in version 5), which adds creation of dynamic web pages; and Internationalized Domain Names (in version 7), which allow Web sites to have native-language addresses with non-Latin characters. The browser has also received scrutiny throughout its development for use of third-party technology (such as the source code of Spyglass Mosaic, used without royalty in early versions) and security and privacy vulnerabilities, and both the United States and the European Union have alleged that integration of Internet Explorer with Windows has been to the detriment of other browsers.

Internet Explorer 10 and 11 on Windows 8.x have two interfaces, one for traditional desktop use and another for tablet/touchscreen use.

OS compatibility

IE versions, over time, have had widely varying OS compatibility, ranging from being available for many platforms and several versions of Windows to only a few versions of Windows. Many versions of IE had some support for an older OS but stopped getting updates. The increased growth of the Internet in the 1990s and 2000s means that current browsers with small market shares have more total users than the entire market early on. For example, 90% market share in 1997 would be roughly 60 million users, but by the start of 2007 90% market share would equate to over 900 million users. The result is that later versions of IE6 had many more users in total than all the early versions put together.

The release of IE7 at the end of 2006 resulted in a collapse of IE6 market share; by February 2007, market version share statistics showed IE6 at about 50% and IE7 at 29%. Regardless of the actual market share, the most compatible version (across operating systems) of IE was 5.x, which had Mac OS 9 and Mac OS X, Unix, and most Windows versions available and supported for a short period in the late 1990s (although 4.x had a more unified codebase across versions). By 2007, IE had much narrower OS support, with the latest versions supporting only Windows XP SP2 and above. Internet Explorer 5.0, 5.5, 6, and 7 (Experimental) have also been unofficially ported to the Linux operating system from the project IEs4Linux.

+ Availability on desktop operating systemsOperating system Latest stable IE version Support date ExceptionsMicrosoft Windows 7 or later, Server 2008 R2 or later 2009– Continued to receive security patches.IE11 was later released for Windows Embedded 8 Standard and Server 2012. Windows Server 2012 will continue to receive security patches until 2026 with ESU 8 2012 Vista and Server 2008 2006–2011 Windows Server 2008 continued to receive security patches until 2023 with ESU (and continued until 2026 with ESU for Azure and Premium Assurance customers) XP and Server 2003 2001–2009 Windows Embedded POSReady 2009 continued to receive security patches until 2019 NT 4.0, 98, 2000 and ME 1996–2001 95 1995–2000 3.1 and NT 3.51 1995–1999 NT 3.5 1995–1996 NT 3.1 1995macOS 10.4–10.6 (IA-32, x64) 5.2.3 (with Rosetta) 2005 10.1–10.5 (PPC) 5.2.3 2001–2003 Classic Mac OS 7.5.5–9.2.2 (PPC) 5.1.7 (included) 1995–2003 7.1–8.1 (68k) 4.0.1 (included) 1995–1998 7.0.1 (68k) 2.1 1995 OS/2 2.1–4.52 3.0 HP-UX 5.01 SP1 Solaris 5.01 SP11995–2001

Versions

Microsoft Internet Explorer 1

Microsoft Internet Explorer 1 made its debut on August 24, 1995. It was a reworked version of Spyglass Mosaic which Microsoft had licensed, like many other companies initiating browser development, from Spyglass Inc. It came with the purchase of Microsoft Plus! for Windows 95 and with at least some OEM releases of Windows 95 without Plus!. It was installed as part of the Internet Jumpstart Kit in Plus! for Windows 95. The Internet Explorer team began with about six people in early development. Version 1.5 was released in fall 1995 for Windows NT and added support for basic HTML table rendering. By including it free of charge on their operating system, they did not have to pay royalties to Spyglass Inc, resulting in a lawsuit and a US$8 million settlement on January 22, 1997.

Although not included, this software can also be installed on the original release of Windows 95.

Internet Explorer 1 is no longer supported, or available for download from Microsoft. However, archived versions of the software can be found on various websites. Support for Internet Explorer 1 ended on December 31, 2001, the same day as older Windows versions.

Features Internet Explorer came with an install routine replacing a manual installation required by many of the existing web browsers.

Microsoft Internet Explorer 2

Microsoft Internet Explorer 2 was released on November 27, 1995 (following a beta in October). It featured support for JavaScript, SSL, cookies, frames, VRML, RSA, and Internet newsgroups. Version 2 was also the first release for Windows 3.1 and Macintosh System 7.0.1 (PPC or 68k), although the Mac version was not released until January 1996 for PPC, and April for 68k. Version 2.1 for the Mac came out in August 1996, although by this time, Windows was getting version 3. Version 2 was included in Windows 95 OSR1, Windows NT 4.0 and Microsoft's Internet Starter Kit. It launched with twelve languages, including English, but by April 1996, this was expanded to 24, 20, and 9 for Windows, and Mac, respectively. The 2.0i version supported double-byte character-set. It is the last version of Internet Explorer to run on Windows NT 3.1.

Microsoft Internet Explorer 3

Market share history snapshotfor February 2005IE4: 0.07%IE5: 6.17%IE6: 82.79% Microsoft Internet Explorer 3 was released on August 13, 1996, and went on to be much more popular than its predecessors. It was the first major browser with CSS support, although this support was only partial. It also introduced support for ActiveX controls, Java applets, inline multimedia, and the PICS system for content metadata. Version 3 also came bundled with Internet Mail and News, NetMeeting, and an early version of the Address Book, and was itself included with Windows 95 OSR2. Version 3 proved to be the first more popular version of Internet Explorer, bringing with it increased scrutiny. In the months following its release, a number of security and privacy vulnerabilities were found by researchers and hackers. This version of Internet Explorer was the first to have the 'blue e' logo. The Internet Explorer team consisted of roughly 100 people during the development of three months. The first major IE security hole, the Princeton Word Macro Virus Loophole, was discovered on August 22, 1996, in IE3.

Backwards compatibility was handled by allowing users who upgraded to IE3 to still use the previous version, because the installation renamed the old version (incorporating the old version number) and stored it in the same directory. It is the last version of Internet Explorer to run on Windows NT 3.5 and Windows NT 4.0 RTM through SP2."By having IE3 rename your previous version, Microsoft gives you a fallback in case IE3 crashes. IE3 also scans for Netscape bookmarks and converts them to IE3 favorites."

Microsoft Internet Explorer 4

Market share history snapshotfor October 2008IE4: 0.01%IE5: 0.20%IE6: 37.01%IE7: 35.81% Microsoft Internet Explorer 4, released on September 22, 1997, deepened the level of integration between the web browser and the underlying operating system. Installing version 4 on Windows 95 or Windows NT 4.0 and choosing Desktop Update would result in the traditional File Explorer being replaced by a version more akin to a web browser interface, as well as the Windows desktop itself being web-enabled via Active Desktop. The integration with Windows, however, was subject to numerous packaging criticisms (see United States v. Microsoft). This option was no longer available with the installers for later versions of Internet Explorer, but was not removed from the system if already installed. It introduced support for Group Policy, allowing companies to configure and lock down many aspects of the browser's configuration as well as support for offline browsing. Internet Mail and News was replaced with Outlook Express, and Microsoft Chat and an improved NetMeeting were also included. This version was also included with Windows 95 OSR 2.5 and Windows 98. New features that allowed users to save and retrieve posts in comment forms were added, but they are not used today. Internet Explorer 4.5 offered new features such as easier 128-bit encryption. It also offered a dramatic stability improvement over prior versions, particularly the 68k version, which was especially prone to freezing.

Microsoft Internet Explorer 5

Microsoft Internet Explorer 5, released on March 18, 1999, and subsequently included with Windows 98 SE and bundled with Office 2000 as an optional component and Office XP as a requirement prior to install, was another significant release that supported bi-directional text, ruby characters, XML, XSLT, and the ability to save web pages in MHTML format. IE5 was bundled with Outlook Express 5. Also, with the release of IE5, Microsoft released the first version of XMLHttpRequest, giving birth to Ajax (even though the term "Ajax" was not coined until years later). It was the last with a 16-bit version. Version 5.01, a bug fix version included in Windows 2000, was released in November 1999 and is the last version of Internet Explorer to run on Windows 3.1 and Windows NT 3.51. Internet Explorer 5.5 followed in June 2000, improving its print preview capabilities, CSS and HTML standards support, and developer APIs; this version was included with Windows ME. However, version 5 was the last version for Mac and UNIX. Version 5.5 was the last to have Compatibility Mode, which allowed Internet Explorer 4 to be run side by side with the 5.x series. The IE team consisted of over 1,000 people by 1999, with funding on the order of per year. Version 5.5 is also the last version of Internet Explorer to run on Windows 95 and Windows NT 4.0 SP3 through SP6.

Microsoft Internet Explorer 6