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PHP Forms and User Input
The PHP $_GET and $_POST variables are used to retrieve information from forms, like user input.
PHP Form Handling
The most important thing to notice when dealing with HTML forms and PHP is that any form element in an HTML page will automatically be available to your PHP scripts.
Form example:
| <html> <body> <form action="welcome.php" method="post"> Name: <input type="text" name="name" /> Age: <input type="text" name="age" /> <input type="submit" /> </form> </body> </html> |
The example HTML page above contains two input fields and a submit button. When the user fills in this form and click on the submit button, the form data is sent to the "welcome.php" file.
The "welcome.php" file looks like this:
<html>
<body>
Welcome
<?php echo $_POST["name"]; ?>
.<br />
You are<?php echo $_POST["age"]; ?> years old.
</body>
</html> |
A sample output of the above script may be:
| Welcome John. You are 28 years old. |
The PHP $_GET and $_POST variables will be explained in the next chapters.
Form Validation
User input should be validated on the browser whenever possible (by client scripts (JavaScript)). Browser validation is faster and you reduce the server load.
You should consider using server validation if the user input will be inserted into a database. A good way to validate a form on the server is to post the form to itself, instead of jumping to a different page. The user will then get the error messages on the same page as the form. This makes it easier to discover the error.
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