Files with DWG extension represent proprietary binary files used for containing 2D and 3D design data. Like DXF, which are ASCII files, DWG represent the binary file format for CAD (Computer Aided Design) drawings. It contains vector image and metadata for representation of contents of CAD files.
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 DWG into many other file formats. Please see the complete list below.