Web Design/Dynamic Websites/Simple Functions in PHP

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Web Design Simple Functions in PHP
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Note: Work in progress PHP.net has a reference on PHP functions, but it's a little complicated for your average beginner.

Example PHP file with function[edit]

Try testing the following PHP file:

<?php

 //
 // A simple function that prints a welcome message
 //
 function welcome()
 {
   print("<h2>Hi there. Welcome to PHP functions</h2>");
   print("<p>Here we'll learn a little about functions</p>");
 }


 welcome();

 welcome();

 welcome();

?>

Can you explain why it does what it does?

Example 2: a function with an argument[edit]

A small modification:

<?php

 //
 // A simple function that prints a welcome message
 //
 function welcome($username)
 {
   print("<h2>Hi there $username. Welcome to PHP functions</h2>");
   print("<p>Here we'll learn a little about functions</p>");
 }


 welcome("Michael");

 welcome("Izaak");

 welcome("Brigitte");

?>

Can you explain what's happening this time?

Example 3: Something more useful[edit]

So far we've done simple PHP templating using include files. But we can replace this with functions to, and give ourselves some extra power while we're at it! Try the following:

<?php

 //
 // A simple function that prints the code that's at the
 // beginning of every page on my site.
 //
 function printHeader()
 {
?>
  <html>
    <head>
      <title>Home page of my site</title>
    </head>
    <body>

      <h1> My website </h1>
      <div id="main">
<?php
 }

 


 printHeader();

 print("<p> The content of my page would go here</p>");

 // printFooter(); // woops, we don't have this function yet!

?>

Again, test out this page and then see if you can explain what it's doing!

Here's the challenge:

  1. See if you can modify your printHeader() function so that you can say: printHeader("Page 2"); - and the text "Page 2" will be displayed in the title tags (look back to a previous example!)
  2. Try creating and using your own printFooter() function.

Of course, we'd remove these functions into an include-file so that we can reuse them on other pages!