[Python编程(第4版)].(Programming.Python.4th.Edition).Mark.Lutz.文字版

This demo shows how to display a "hello world" message in various
programming languages' syntax. To keep this simple, only the output command
is shown (it takes more code to make a complete program in some of these
languages), and only text-based solutions are given (no GUI or HTML
construction logic is included). This page is a simple HTML file; the one
you see after pressing the button below is generated by a Python CGI script
which runs on the server. Pointers:

• To see this page's HTML, use the 'View Source' command in your browser.
  
• To view the Python CGI script on the server,
  click here or
  here.
  
• To see an alternative version that generates this page dynamically,
  click here.
  

For the moment, let’s ignore some of the hyperlinks near the middle of this file; they
introduce bigger concepts like file transfers and maintainability that we will explore in
the next two sections. When visited with a browser, this HTML file is downloaded to
the client and is rendered into the new browser page shown in Figure 15-21.

That widget above the Submit button is a pull-down selection list that lets you choose
one of the tag values in the HTML file. As usual, selecting one of these language
names and pressing the Submit button at the bottom (or pressing your Enter key) sends
the selected language name to an instance of the server-side CGI script program named
in the form’s action option. Example 15-18 contains the Python script that is run by
the web server upon submission.

1184 | Chapter 15: Server-Side Scripting