Forms
Method nr. 1 - two files
Main file
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="PHP basics">
<title>Multiplication table</title>
</head>
<body>
<h3>Enter the multiplication table range</h3>
<form action="multiplication_table.php" method="post">
<p>Number of rows:</p>
<input type="text" name="n">
<p>Number of columns:</p>
<input type="text" name="m">
<br><br>
<input type="submit" value="Submit">
</form>
</body>
</html>
Second file
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="PHP basics">
<title>Multiplication table</title>
<style>
table, td {
border: 1px solid black;
border-spacing: 0;
}
</style>
</head>
<body>
<?php
$n = $_POST['n']; // receiving the value using the POST method
$m = $_POST['m'];
echo "<table>";
for ($i = 1; $i <= $n; $i++) {
echo "<tr>";
for ($j = 1; $j <= $m; $j++)
echo "<td>" . ($i * $j) . "</td>";
echo "</tr>";
}
echo "</table>";
?>
</body>
</html>
Method nr. 2 - one file (PostBack)
We can interleave the PHP tags between instructions. For example, we can exit PHP in the middle of an else instruction, put some HTML elements there that will only display if this instruction was executed, and then come back to PHP.
The isset() method checks if a variable is set and is not null. It returns true if the variable exists and is not null, and false otherwise.
The empty() method determines if a variable is empty, meaning it is unset, null, false, an empty string, 0, or an empty array. It returns true if the variable is empty and false if it has a non-empty value.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="PHP basics">
<title>PostBack</title>
</head>
<body>
<?php function form($firstName = "", $lastName = "", $profession = "", $email = "", $mailingChecked = false, $gender = "", $education = "")
{ ?>
<form action="" method="post">
<div>
<p>First name:</p>
<input name="firstName" value="<?= $firstName; ?>"><br>
<p>Last name:</p>
<input name="lastName" value="<?= $lastName; ?>"><br>
<p>Profession:</p>
<input name="profession" value="<?= $profession; ?>"><br>
<p>Email address:</p>
<input name="email" value="<?= $email; ?>"><br>
<p>Gender:</p>
<input type="radio" name="gender" value="Male" <?php if ($gender === "Male") echo "checked"; ?>><label for="Male">Male</label><br>
<input type="radio" name="gender" value="Female" <?php if ($gender === "Female") echo "checked"; ?>><label for="Female">Female</label><br>
<p>Education:</p>
<select name="education">
<option value="">-- Select --</option>
<option value="High School" <?php if ($education === "High School") echo "selected"; ?>>High School</option>
<option value="Bachelor's" <?php if ($education === "Bachelor's") echo "selected"; ?>>Bachelor's</option>
<option value="Master's" <?php if ($education === "Master's") echo "selected"; ?>>Master's</option>
<option value="PhD" <?php if ($education === "PhD") echo "selected"; ?>>PhD</option>
</select><br><br>
<input type="checkbox" name="mailing" <?php if ($mailingChecked) echo "checked"; ?>>I want to receive commercial information<br><br>
<input type="submit" value="Submit" name="submit">
</div>
</form>
<?php } ?>
<?php
if (isset($_POST["submit"])) {
$mailing = isset($_POST["mailing"]);
$gender = isset($_POST["gender"]) ? $_POST["gender"] : "";
$education = isset($_POST["education"]) ? $_POST["education"] : "";
form($_POST["firstName"], $_POST["lastName"], $_POST["profession"], $_POST["email"], $mailing, $gender, $education);
if (empty($_POST["firstName"]) || empty($_POST["lastName"]) ||
empty($_POST["profession"]) || empty($_POST["email"]) ||
empty($gender) || empty($education)) {
echo "<p style='color: red;'>You must fill in all fields!</p>";
} else {
echo "<p>Thank you for filling out the form!</p>";
?>
<ul>
<li>First name: <b><?= trim($_POST["firstName"]); ?></b></li>
<li>Last name: <b><?= trim($_POST["lastName"]); ?></b></li>
<li>Profession: <b><?= trim($_POST["profession"]); ?></b></li>
<li>Email address: <b><?= trim($_POST["email"]); ?></b></li>
<li>Gender: <b><?= $gender; ?></b></li>
<li>Education: <b><?= $education; ?></b></li>
<?php
if ($mailing)
echo "<li>You want to receive commercial information.</li>";
else
echo "<li>You do not want to receive commercial information.</li>";
?>
</ul>
<?php
}
} else
form();
?>
</body>
</html>