Some languages are traditional programming languages for developing applications; others, such as markup and scripting languages like html, xhtml, and are designed to be used to create web pages.

XML (Extensible Markup Language):

Explanation:

XML (Xtensible Markup Language):

It is a markup language that is used for creating web-pages, it defines a set of rules that makes it readable both to humans and machine.

XML was primarily designed to be a software and hardware independent tool and it's focus was on data.  XML provides a framework for defining markup languages.

XML, HTML and XHTML are all related to each other because they are all markup languages and can be used to build websites.

Basically,

-HTML is primarily for web-pages.

-XML is primarily for data.

-XHTML is a standard based on HTML that follows the strict rules of XML.

the answer to your question would be something called hertz. the unit of measurement called a hertz, which is one cycle per second, is used to measure clock speed. within one cycle, your computer processes, refreshes, or updates itself to the changes that it is going through. in the case of computer clock speed, one hertz equals one tick per second. the clock speed of computers is usually measured in megahertz (mhz) or gigahertz (ghz)