Convert xhtm to fits

What is the difference between .xhtm and .fits?

Name: Extensible Hypertext Markup Language File; Flexible Image Transport System File

Description: The Extensible Hypertext Markup Language (XHTML) file type is an XML-based markup language for creating web pages. It is a hybrid of HTML and XML and is designed to replace HTML as the main language for creating web content. XHTML files provide a more flexible, extensible structure for web documents, allowing for more complex page designs and better integration with other web technologies.; The Flexible Image Transport System (FITS) file format is a digital file format used primarily in astronomy for storing, transmitting, and analyzing scientific images and data. Developed in the late 1970s, FITS was designed to provide a standard for the interchange of astronomical data, facilitating the sharing and analysis of data among astronomers and researchers worldwide.