HTML Application

An HTML Application (HTA) is a Microsoft Windows program whose source code consists of HTML, Dynamic HTML, and one or more scripting languages supported by Internet Explorer, such as VBScript or JScript. The HTML is used to generate the user interface, and the scripting language is used for the program logic. An HTA executes without the constraints of the internet browser security model; in fact, it executes as a 'fully trusted' application. An HTML Application (HTA) is a Microsoft Windows program whose source code consists of HTML, Dynamic HTML, and one or more scripting languages supported by Internet Explorer, such as VBScript or JScript. The HTML is used to generate the user interface, and the scripting language is used for the program logic. An HTA executes without the constraints of the internet browser security model; in fact, it executes as a 'fully trusted' application. The usual file extension of an HTA is .hta. The ability to execute HTAs was introduced to Microsoft Windows in 1999, along with the release of Microsoft Internet Explorer 5. On December 9, 2003 this technology was patented. HTAs give the developer the features of HTML together with the advantages of scripting languages. They are popular with Microsoft system administrators who use them for system administration from prototypes to 'full-scale' applications, especially where flexibility and speed of development are critical. An HTA is executed using the program mshta.exe, or, alternatively, double-clicking on the file. This program is typically installed along with Internet Explorer. mshta.exe executes the HTA by instantiating the Internet Explorer rendering engine (mshtml) as well as any required language engines (such as vbscript.dll). An HTA is treated like any executable file with extension .exe. When executed via mshta.exe (or if the file icon is double-clicked), it runs immediately. When executed remotely via the browser, the user is asked once, before the HTA is downloaded, whether or not to save or run the application; if saved, it can simply be run on demand after that. By default, HTAs are rendered as per 'standards-mode content in IE7 Standards mode and quirks mode content in IE5 (Quirks) mode', but this can be altered using X-UA-Compatible headers. The HTA engine (mshta.exe) is dependent on Internet Explorer. Starting from Windows Vista, a user can remove Internet Explorer from Windows, which will cause the HTA engine to stop working. HTAs are fully supported in Internet Explorer from versions 5 to 9. Further versions, such as 10 and 11, still support HTAs though with some minor features turned off.