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Unit 9: Working with Forms
11. print “<ul>\n\n”; Notes
12. ?>
13. </body>
14. </html>
9.4 Combining HTML and PHP Code on a Single Page
In some circumstances, you might want to include form-parsing code on the same page as a
hard- coded HTML form. Such a combination can be useful if you need to present the same
form to the user more than once. You would have more flexibility if you were to write the
entire page dynamically, of course, but you would miss out on one of the great strengths of
PHP. The more standard HTML you can leave in your pages, the easier they are for designers
and page builders to amend without reference to you. You should avoid scattering substantial
chunks of PHP code throughout your documents, however. Doing so makes them hard to read
and maintain. Where possible, you should create functions that can be called from within your
HTML code and can be reused in other projects.
For the following examples, imagine that we’re creating a site that teaches basic math to preschool
children, and have been asked to create a script that takes a number from form input and tells
the user whether it’s larger or smaller than a predefined integer.
Listing 6 creates the HTML. For this example, we need only a single text field, but even so,
we’ll include a little PHP.
Listing 6 An HTML Form That Calls Itself
1. <html>
2. <head>
3. <title>Listing 6 An HTML form that calls itself</title>
4. </head>
5. <body>
6. <form action=”< ?php print $_SERVER[PHP_SELF] ? >” method=”POST”>
7. Type your guess here: <input type=”text” name=”guess”>
8. </form>
9. </body>
10. </html>
The action of this script is $_SERVER[PHP_SELF]. This variable is the equivalent of the name
of the current script. In other words, the action tells the script to reload itself.
The script in Listing 6 doesn’t produce any output. In Listing 7, we begin to build up the PHP
element of the page. First, we must define the number that the user guesses. In a fully working
version, we’d probably randomly generate this number, but for now, we keep it simple. We
assign 42 to the $num_to_guess variable on line 2. Next, we must determine whether the form
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