User input should be validated on the browser whenever possible (by client scripts). Browser validation is faster and reduces the server load. The PHP $_GET and $_POST variables are used to retrieve information from forms, like user input. The $_GET Variable The predefined $_GET variable is used to collect values in a form with method=”get” Information sent from a form with the GET method is visible to everyone (it will be displayed in the browser’s address bar) and has limits on the amount of information to send. Example <form action=”welcome.php” method=”get”> Name: <input type=”text” name=”fname” /> Age: <input type=”text” name=”age” /> <input type=”submit” /> </form> When the user clicks the “Submit” button, the URL sent to the server could look something like this: http://localhost/welcome.php?fname=Peter&age=37 The “welcome.php” file can now use the $_GET variable to collect form data (the names of the form fields will ...