yunchih/simpleFormValidation.php

## simpleFormValidation.php
<?php
  error_reporting(E_ERROR | E_WARNING | E_PARSE);
  /*
   * Turn off notice so that empty array
   * like $value and $error
   * won't be taken as undefined array.
   */
?>
<!DOCTYPE HTML>
<html>
  <head>
    <style>
      .error {
        color: #FF0000;
      }
      .error:first-letter {
          text-transform: uppercase;
      }
    </style>
  </head>
<body>

<?php
$requiredField = array("name","email","gender");
$checkValid = array(
  "name"=> function($name){
            if (!preg_match("/^[a-zA-Z ]*$/",$name))
              return "Only letters and white space allowed";
          },
  "email"=> function($email){
            if (!filter_var($email, FILTER_VALIDATE_EMAIL))
              return "Invalid email format";
          },
  "website"=> function($website){
            $pattern ="/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i";
            if (!preg_match($pattern,$website))
              return "Invalid URL";
          }
);
$error = array();
$value = array();

function getInput($field){
  if (empty($_POST[$field])) {
    $input = "";
  }
  else{
    $input = trim($_POST[$field]);
    $input = stripslashes($input);
    $input = htmlspecialchars($input);
  }
  return $input;
}
if ($_SERVER["REQUEST_METHOD"] == "POST") {
   foreach ($requiredField as $field) {
      $input = getInput($field);
      if($input!=""){
        $value[$field] = $input;
        $error[$field] = $checkValid[$field]($input);
        var_dump($checkValid[$field]($input));
        /*
         * The bug is here.
         * The compiler says:
         * Fatal error: Function name must be a string
         * but the following expression passes:
         * $error[$field] = $checkValid["name"]($input);
         *
         * Some minor observations:
         * var_dump($field) ===> string(4) "name"
         * //So $field is really a String!!!!!
         *
         *
         * var_dump($checkValid[$field]) ===>
         * object(Closure)#1 (1) {
         *    ["parameter"]=> array(1) { ["$name"]=> string(10) "" }
         * }
         *
         * var_dump($checkValid[$field]($input)) ==>
         * string(20) "Invalid email format"
         *
         */
      }
      else{
        $error[$field] = $field . " is required!";
      }
   }
}
/*
 * $value and $error preceded by "global"
 * Such a weird scope rule never seen in other
 * language.
 */
function putValue($field){
  global $value;
  if(isset($value[$field]))
    echo $value[$field];
}
function putError($field){
  global $error;
  if(isset($error[$field]))
    echo "<span class='error'>" . $error[$field] . "</span>";
}

if(empty($error) && !empty($value)):
  echo "<h2>Your Input:</h2>";
  foreach ($value as $field => $fieldValue) {
    echo $field . " is " . $fieldValue;
  }
else:
?>
<h2>PHP Form Validation Example</h2>
  <form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
   Name: <input type="text" name="name" value="<?php putValue('name');?>">
   <?php putError("name"); ?>
   <br><br>
   E-mail: <input type="text" name="email" value="<?php putValue('email');?>">
   <?php putError("email"); ?>
   <br><br>
   Website: <input type="text" name="website" value="<?php putValue('website');?>">
   <?php putError("website"); ?>
   <br><br>
   Comment: <textarea name="comment" rows="5" cols="40"><?php echo putValue('comment');?></textarea>
   <br><br>
   Gender:
   <input type="radio" name="gender" <?php if (isset($value['gender']) && $value['gender']=="female") echo "checked";?>  value="female">Female
   <input type="radio" name="gender" <?php if (isset($value['gender']) && $value['gender']=="male") echo "checked";?>  value="male">Male
   <?php putError("gender"); ?>
   <br><br>
   <input type="submit" name="submit" value="Submit">
</form>

<?php endif; ?>

</body>
</html>
	<?php
	error_reporting(E_ERROR \| E_WARNING \| E_PARSE);
	/*
	* Turn off notice so that empty array
	* like $value and $error
	* won't be taken as undefined array.
	*/
	?>
	<!DOCTYPE HTML>
	<html>
	<head>
	<style>
	.error {
	color: #FF0000;
	}
	.error:first-letter {
	text-transform: uppercase;
	}
	</style>
	</head>
	<body>

	<?php
	$requiredField = array("name","email","gender");
	$checkValid = array(
	"name"=> function($name){
	if (!preg_match("/^[a-zA-Z ]*$/",$name))
	return "Only letters and white space allowed";
	},
	"email"=> function($email){
	if (!filter_var($email, FILTER_VALIDATE_EMAIL))
	return "Invalid email format";
	},
	"website"=> function($website){
	$pattern ="/\b(?:(?:https?\|ftp):\/\/\|www\.)[-a-z0-9+&@#\/%?=~_\|!:,.;]*[-a-z0-9+&@#\/%=~_\|]/i";
	if (!preg_match($pattern,$website))
	return "Invalid URL";
	}
	);
	$error = array();
	$value = array();

	function getInput($field){
	if (empty($_POST[$field])) {
	$input = "";
	}
	else{
	$input = trim($_POST[$field]);
	$input = stripslashes($input);
	$input = htmlspecialchars($input);
	}
	return $input;
	}
	if ($_SERVER["REQUEST_METHOD"] == "POST") {
	foreach ($requiredField as $field) {
	$input = getInput($field);
	if($input!=""){
	$value[$field] = $input;
	$error[$field] = $checkValid[$field]($input);
	var_dump($checkValid[$field]($input));
	/*
	* The bug is here.
	* The compiler says:
	* Fatal error: Function name must be a string
	* but the following expression passes:
	* $error[$field] = $checkValid["name"]($input);
	*
	* Some minor observations:
	* var_dump($field) ===> string(4) "name"
	* //So $field is really a String!!!!!
	*
	*
	* var_dump($checkValid[$field]) ===>
	* object(Closure)#1 (1) {
	* ["parameter"]=> array(1) { ["$name"]=> string(10) "" }
	* }
	*
	* var_dump($checkValid[$field]($input)) ==>
	* string(20) "Invalid email format"
	*
	*/
	}
	else{
	$error[$field] = $field . " is required!";
	}
	}
	}
	/*
	* $value and $error preceded by "global"
	* Such a weird scope rule never seen in other
	* language.
	*/
	function putValue($field){
	global $value;
	if(isset($value[$field]))
	echo $value[$field];
	}
	function putError($field){
	global $error;
	if(isset($error[$field]))
	echo "<span class='error'>" . $error[$field] . "</span>";
	}

	if(empty($error) && !empty($value)):
	echo "<h2>Your Input:</h2>";
	foreach ($value as $field => $fieldValue) {
	echo $field . " is " . $fieldValue;
	}
	else:
	?>
	<h2>PHP Form Validation Example</h2>
	<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
	Name: <input type="text" name="name" value="<?php putValue('name');?>">
	<?php putError("name"); ?>
	<br><br>
	E-mail: <input type="text" name="email" value="<?php putValue('email');?>">
	<?php putError("email"); ?>
	<br><br>
	Website: <input type="text" name="website" value="<?php putValue('website');?>">
	<?php putError("website"); ?>
	<br><br>
	Comment: <textarea name="comment" rows="5" cols="40"><?php echo putValue('comment');?></textarea>
	<br><br>
	Gender:
	<input type="radio" name="gender" <?php if (isset($value['gender']) && $value['gender']=="female") echo "checked";?> value="female">Female
	<input type="radio" name="gender" <?php if (isset($value['gender']) && $value['gender']=="male") echo "checked";?> value="male">Male
	<?php putError("gender"); ?>
	<br><br>
	<input type="submit" name="submit" value="Submit">
	</form>

	<?php endif; ?>

	</body>
	</html>