PHP 表单验证 - 验证 E-mail 和 URL

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本节展示如何验证名字、电邮和 URL。

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PHP - 验证名字

以下代码展示的简单方法检查 name 字段是否包含字母和空格。如果 name 字段无效，则存储一条错误消息：

 $name = test_input($_POST["name"]);

 if (!preg_match("/^[a-zA-Z ]*$/",$name)) {

   $nameErr = "只允许字母和空格！";

 }

注释：preg_match() 函数检索字符串的模式，如果模式存在则返回 true，否则返回 false。

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PHP - 验证 E-mail

以下代码展示的简单方法检查 e-mail 地址语法是否有效。如果无效则存储一条错误消息：

 $email = test_input($_POST["email"]);

 if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {

   $emailErr = "无效的 email 格式！";

 }

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PHP - 验证 URL

以下代码展示的方法检查 URL 地址语法是否有效（这条正则表达式同时允许 URL 中的斜杠）。如果 URL 地址语法无效，则存储一条错误消息：

 $website = test_input($_POST["website"]);

 if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%

 =~_|]/i",$website)) {

   $websiteErr = "无效的 URL";

 }

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PHP - 验证 Name、E-mail、以及 URL

现在，脚本是这样的：

实例

 <?php

 // 定义变量并设置为空值

 $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"]);

     // 检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"]);

     // 检查电邮地址语法是否有效

     if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {

       $emailErr = "Invalid email format";

     }

   }

   if (empty($_POST["website"])) {

     $website = "";

   } else {

     $website = test_input($_POST["website"]);

     // 检查 URL 地址语言是否有效（此正则表达式同样允许 URL 中的下划线）

     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"]);

   }

 }

 ?>

源代码：

 <!DOCTYPE HTML>

 <html>

 <head>

 <style>

 .error {color: #FF0000;}

 </style>

 </head>

 <body> 

 <?php

 // 定义变量并设置为空值

 $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"]);

      // 检查姓名是否包含字母和空白字符

      if (!preg_match("/^[a-zA-Z ]*$/",$name)) {

        $nameErr = "只允许字母和空格";

      }

    }

    if (empty($_POST["email"])) {

      $emailErr = "电邮是必填的";

    } else {

      $email = test_input($_POST["email"]);

      // 检查电子邮件地址语法是否有效

      if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {

        $emailErr = "无效的 email 格式";

      }

    }

    if (empty($_POST["website"])) {

      $website = "";

    } else {

      $website = test_input($_POST["website"]);

      // 检查 URL 地址语法是否有效（正则表达式也允许 URL 中的斜杠）

      if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {

        $websiteErr = "无效的 URL";

      }

    }

    if (empty($_POST["comment"])) {

      $comment = "";

    } else {

      $comment = test_input($_POST["comment"]);

    }

    if (empty($_POST["gender"])) {

      $genderErr = "性别是必选的";

    } else {

      $gender = test_input($_POST["gender"]);

    }

 }

 function test_input($data) {

    $data = trim($data);

    $data = stripslashes($data);

    $data = htmlspecialchars($data);

    return $data;

 }

 ?>

 <h2>PHP 验证实例</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>

    电邮：<input type="text" name="email">

    <span class="error">* <?php echo $emailErr;?></span>

    <br><br>

    网址：<input type="text" name="website">

    <span class="error"><?php echo $websiteErr;?></span>

    <br><br>

    评论：<textarea name="comment" rows="" cols=""></textarea>

    <br><br>

    性别：

    <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>您的输入：</h2>";

 echo $name;

 echo "<br>";

 echo $email;

 echo "<br>";

 echo $website;

 echo "<br>";

 echo $comment;

 echo "<br>";

 echo $gender;

 ?>

 </body>

 </html>

运行结果：

接下来向您讲解如何防止表单在用户提交表单后清空所有输入字段。