You want to use a form that displays more than one page and preserves data from one page to the next.
For example, your form is for a survey that has too many questions to put them all on one page.
Use session tracking to store form information for each stage as well as a variable to keep track of what stage to display.
Example 9-21 displays the four files for a two pageform and showing the collected results.
Example 9-21. Making a multipage form
The “deciding what to do” logic (stage.php):
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// Turn on sessions session_start(); // Figure out what stage to use if (($_SERVER['REQUEST_METHOD'] == 'GET') || (! isset($_POST['stage']))) { $stage = 1; } else { $stage = (int) $_POST['stage']; } // Make sure stage isn't too big or too small $stage = max($stage, 1); $stage = min($stage, 3); // Save any submitted data if ($stage > 1) { foreach ($_POST as $key => $value) { $_SESSION[$key] = $value; } } include __DIR__ . "/stage-$stage.php"; |
The first page of the form (stage-1.php):
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<form action='<?= htmlentities($_SERVER['SCRIPT_NAME']) ?>' method='post'> Name: <input type='text' name='name'/> <br/> Age: <input type='text' name='age'/> <br/> <input type='hidden' name='stage' value='<?= $stage + 1 ?>'/> <input type='submit' value='Next'/> </form> |
The second page of the form (stage-2.php):
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<form action='<?= htmlentities($_SERVER['SCRIPT_NAME']) ?>' method='post'> Favorite Color: <input type='text' name='color'/> <br/> Favorite Food: <input type='text' name='food'/> <br/> <input type='hidden' name='stage' value='<?= $stage + 1 ?>'/> <input type='submit' value='Done'/> |
The displaying-results page (stage-3.php):
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Hello <?= htmlentities($_SESSION['name']) ?>. You are <?= htmlentities($_SESSION['age']) ?> years old. Your favorite color is <?= htmlentities($_SESSION['color']) ?> and your favorite food is <?= htmlentities($_SESSION['food']) ?>. |
At the beginning of each stage in Example 9-21, all the submitted form variables are copied into $_SESSION.
This makes them available on subsequent requests, including the code that runs in stage 3, which displays everything that’s been saved.
PHP’s sessions are perfect for this kind of task since all of the data in a session is stored on the server.
This keeps each request small—no need to resubmit stuff that’s been entered on a previous stage—and reduces the validation overhead.
You only have to validate each piece of submitted data when it’s submitted.
