A "Web Browser" is simply a web program that attempts to
interpret and correctly display text that has been formatted with the
Hypertext Markup Language format (HTML).
Just like a web server typically does not care who it is giving
data too, a web browser typically does not care where it is getting
data from. They both continue as long as the other end continues to
play by the rules.
For example, most web browsers will read directly from a file.
Create a file with the following contents:
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<HTML><HEAD>
<TITLE>Hello World</TITLE>
</HEAD><BODY>
<H1>Hello World</H1>
Hello world, from a <EM> simple </EM> text file with imbedded HTML formatting.
<HR>
</BODY></HTML>
We can then open that file directly with the web browser. Try it.
Note how the browser followed our formatting instructions to
display the specified data.