PHP教學-表單驗證 - 驗證 E-mail 和 URL


PHP - 驗證名字
以下程式碼展示的簡單方法檢查 name 字段是否包含字母和空格。如果 name 字段無效,則存儲一條錯誤消息:
$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
  $nameErr = "只允許字母和空格!"; 
}
註釋:preg_match() 函數檢索字串的模式,如果模式存在則返回 true,否則返回 false。
PHP - 驗證 E-mail
以下程式碼展示的簡單方法檢查 e-mail 地址語法是否有效。如果無效則存儲一條錯誤消息:
$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
  $nameErr = "只允許字母和空格!"; 
}
PHP - 驗證 URL
以下程式碼展示的方法檢查 URL 地址語法是否有效(這條正則表達式同時允許 URL 中的斜槓)。如果 URL 地址語法無效,則存儲一條錯誤消息:
$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
  $nameErr = "只允許字母和空格!"; 
}
PHP - 驗證 Name、E-mail、以及 URL
現在,scripts是這樣的:
範例
<?php
// 定義變數並設置為空值
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
  if (empty($_POST["name"])) {
    $nameErr = "Name is required";
  } else {
    $name = test_input($_POST["name"]);
    // 檢查名字是否包含字母和空格
    if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
      $nameErr = "Only letters and white space allowed";
    }
  }
  if (empty($_POST["email"])) {
    $emailErr = "Email is required";
  } else {
    $email = test_input($_POST["email"]);
    // 檢查電郵地址語法是否有效
    if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {
      $emailErr = "Invalid email format";
    }
  }
  if (empty($_POST["website"])) {
    $website = "";
  } else {
    $website = test_input($_POST["website"]);
    // 檢查 URL 地址語言是否有效(此正則表達式同樣允許 URL 中的下劃線)
    if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%
    =~_|]/i",$website)) {
      $websiteErr = "Invalid URL";
    }
  }
  if (empty($_POST["comment"])) {
    $comment = "";
  } else {
    $comment = test_input($_POST["comment"]);
  }
  if (empty($_POST["gender"])) {
    $genderErr = "Gender is required";
  } else {
    $gender = test_input($_POST["gender"]);
  }
}
?>

完整範例
<!DOCTYPE HTML> 
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body> 
<?php
// 定義變數並設置為空值
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
   if (empty($_POST["name"])) {
     $nameErr = "姓名是必填的";
   } else {
     $name = test_input($_POST["name"]);
     // 檢查姓名是否包含字母和空白字符
     if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
       $nameErr = "只允許字母和空格"; 
     }
   } 
   if (empty($_POST["email"])) {
     $emailErr = "電郵是必填的";
   } else {
     $email = test_input($_POST["email"]);
     // 檢查電子郵件地址語法是否有效
     if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {
       $emailErr = "無效的 email 格式"; 
     }
   }     
   if (empty($_POST["website"])) {
     $website = "";
   } else {
     $website = test_input($_POST["website"]);
     // 檢查 URL 地址語法是否有效(正則表達式也允許 URL 中的斜槓)
     if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
       $websiteErr = "無效的 URL"; 
     }
   }
   if (empty($_POST["comment"])) {
     $comment = "";
   } else {
     $comment = test_input($_POST["comment"]);
   }

   if (empty($_POST["gender"])) {
     $genderErr = "性別是必選的";
   } else {
     $gender = test_input($_POST["gender"]);
   }
}
function test_input($data) {
   $data = trim($data);
   $data = stripslashes($data);
   $data = htmlspecialchars($data);
   return $data;
}
?>
<h2>PHP 驗證範例</h2>
<p><span class="error">* 必需的字段</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>"> 
   姓名:<input type="text" name="name">
   <span class="error">* <?php echo $nameErr;?></span>
   <br><br>
   電郵:<input type="text" name="email">
   <span class="error">* <?php echo $emailErr;?></span>
   <br><br>
   網址:<input type="text" name="website">
   <span class="error"><?php echo $websiteErr;?></span>
   <br><br>
   評論:<textarea name="comment" rows="5" cols="40"></textarea>
   <br><br>
   性別:
   <input type="radio" name="gender" value="female">女性
   <input type="radio" name="gender" value="male">男性
   <span class="error">* <?php echo $genderErr;?></span>
   <br><br>
   <input type="submit" name="submit" value="提交"> 
</form>
<?php
echo "<h2>您的輸入:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>

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