Simple Registration Form Validation in PHP

	<form method="post" action="index.php">
        	<table>
            	<tr>
                	<td colspan="2">
                		<!-- This PHP script is will display the success message of the registration -->
                		<?php if(isset($successful)){ echo $successful; } ?>
            		</td>
                </tr>
            	<tr>
                	<td><input type="text" name="fname" id="fname" placeholder="First Name" value="<?php if(isset($_POST['fname'])){echo $_POST['fname'];} ?>"></td>
                    <td><input type="text" name="lname" id="lname" placeholder="Last Name" value="<?php if(isset($_POST['lname'])){echo $_POST['lname'];} ?>"></td>
                </tr>
                <tr>
                	<td>
                		<!-- This PHP script will display when the form is submitted in First Name field is empty -->
                		<?php if(isset($errors['fname'])){echo "<h2>" .$errors['fname']. "</h2>"; } ?>
                	</td>
                    <td>
                		<!-- This PHP script will display when the form is submitted in Last Name field is empty -->
                    	<?php if(isset($errors['lname'])){echo "<h2>" .$errors['lname']. "</h2>"; } ?>
                    </td>
                </tr>
                <tr>
                	<!-- The PHP Script in value attribute of the input below is use for value retrieval when registration fails due to validations -->
                	<td colspan="2"><input type="text" name="email" id="email" placeholder="E-mail Address" value="<?php if(isset($_POST['email'])){echo $_POST['email'];} ?>"></td>
                </tr>
                <tr>
                    <td colspan="2"><?php if(isset($errors['email'])){echo "<h2>" .$errors['email']. "</h2>"; } ?></td>
                </tr>
                <tr>
                	<td colspan="2"><input type="password" name="password" id="pw" placeholder="Password" value="<?php if(isset($_POST['password'])){echo $_POST['password'];} ?>"></td>
                </tr>
                <tr>
                    <td colspan="2"><?php if(isset($errors['password'])){echo "<h2>" .$errors['password']. "</h2>"; } ?></td>
                </tr>
                <tr>
                	<td colspan="2"><input type="password" name="confirm_password" id="cpw" placeholder="Confirm Password" value="<?php if(isset($_POST['confirm_password'])){echo $_POST['confirm_password'];} ?>">
                </tr>
                <tr>
                    <td colspan="2"><?php if(isset($errors['confirm_password'])){echo "<h2>" .$errors['confirm_password']. "</h2>"; } ?></td>
                </tr>
                <tr>
                    <td><input type="submit" name="submit" id="submit" value="Sign Up"></td>
                </tr>
            </table>
		</form>

	<?php
	$con = mysqli_connect("localhost","root","","form_validation");
 
	$errors = array();
 
	if($_SERVER['REQUEST_METHOD'] == 'POST'){
 
	if(preg_match("/\S+/", $_POST['fname']) === 0){
		$errors['fname'] = "* First Name is required.";
	}
	if(preg_match("/\S+/", $_POST['lname']) === 0){
		$errors['lname'] = "* Last Name is required.";
	}
	if(preg_match("/.+@.+\..+/", $_POST['email']) === 0){
		$errors['email'] = "* Not a valid e-mail address.";
	}
	if(preg_match("/.{8,}/", $_POST['password']) === 0){
		$errors['password'] = "* Password Must Contain at least 8 Chanacters.";
	}
	if(strcmp($_POST['password'], $_POST['confirm_password'])){
		$errors['confirm_password'] = "* Password do not much.";
	}
 
	if(count($errors) === 0){
		$fname = mysqli_real_escape_string($con, $_POST['fname']);
		$lname = mysqli_real_escape_string($con, $_POST['lname']);
		$email = mysqli_real_escape_string($con, $_POST['email']);
 
		$password = hash('sha256', $_POST['password']);
		function createSalt(){
   			$string = md5(uniqid(rand(), true));
    		return substr($string, 0, 3);
		}
		$salt = createSalt();
		$password = hash('sha256', $salt . $password);
 
		$search_query = mysqli_query($con, "SELECT * FROM members WHERE email = '$email'");
		$num_row = mysqli_num_rows($search_query);
		if($num_row >= 1){
			$errors['email'] = "Email address is unavailable.";
		}else{
			$sql = "INSERT INTO members(`fname`, `lname`, `email`, `salt`, `password`) VALUES ('$fname', '$lname', '$email', '$salt', '$password')";
			$query = mysqli_query($con, $sql);
			$_POST['fname'] = '';
			$_POST['lname'] = '';
			$_POST['email'] = '';
 
			$successful = "<h3> You are successfully registered.</h3>";
		}
	}
	}
?>