The MHTML (MIME HTML) filetype, also known as MHT, represents a method for archiving web pages in a single file. Its origins date back to the late 1990s, with its standard being formalized by the Internet Engineering Task Force (IETF) in the RFC 2557 document "Multipurpose Internet Mail Extensions (MIME) Part Three: Message Header Extensions for Non-ASCII Text." MHTML files encapsulate HTML code, images, Java applets, Flash animations, and other resources of a web page, binding them into one file by utilizing the MIME structure.
How MHTML Works
MHTML functions by converting all the external resources of a webpage into MIME format, which is the same standard used for email. In an MHTML file, resources such as images and scripts are encoded and included directly in the file, instead of being linked as external references. This ensures that all the content of the page is preserved exactly as it is seen online, making it a valuable tool for offline viewing and archival purposes.
Software Support for MHTML
Various browsers and email clients support MHTML files. Internet Explorer has historically allowed users to save pages as MHTML files. Microsoft Edge and Microsoft Word can also open these files. However, other popular browsers like Mozilla Firefox and Google Chrome require additional extensions or plugins to handle MHTML files.
Alternatives to MHTML
Although MHTML serves as a comprehensive format for saving web pages, there exist alternative methods for archiving. The most common alternative is to save pages as complete HTML, which creates a folder with all the necessary files alongside the HTML document. PDF can also be used for saving web pages, offering the advantage of being widely viewable on different devices. Additionally, newer file formats and web services like Pocket and Evernote provide capabilities to save, annotate, and share web content with more functionality compared to traditional methods like MHTML.