A file with an .ai extension is an Adobe Illustrator Artwork file that contains vector graphics on a single page. It uses points to create paths for displaying the image data, thus making it safe from losing image quality if it is enlarged. AI format finds its major usage for logos and print media. AI files can be opened with Adobe Illustrator, Adobe Acrobat DC, PaintShop Pro, and CorelDraw Graphics tools.
HTML (Hyper Text Markup Language) is the extension for web pages created for display in browsers. Known as language of the web, HTML has evolved with requirements of new information requirements to be displayed as part of web pages. The latest variant is known as HTML 5 that gives a lot of flexibility for working with the language. HTML pages are either received from server, where these are hosted, or can be loaded from local system as well.
You can also convert AI into many other file formats. Please see the complete list below.