1.经过PHP来验证表单数据php
<!DOCTYPE HTML> <html> <head> </head> <body> <?php // define variables and set to empty values $name = $email = $gender = $comment = $website = ""; if ($_SERVER["REQUEST_METHOD"] == "POST") { $name = test_input($_POST["name"]); $email = test_input($_POST["email"]); $website = test_input($_POST["website"]); $comment = test_input($_POST["comment"]); $gender = test_input($_POST["gender"]); } function test_input($data) { $data = trim($data);//( PHP trim() 函数)去除用户输入数据中没必要要的字符(多余的空格、制表符、换行) $data = stripslashes($data);//(PHP stripslashes() 函数)删除用户输入数据中的反斜杠(\) $data = htmlspecialchars($data); /*(htmlspecialchars() 函数)把特殊字符转换为 HTML 实体。< 和 > 之类的 HTML 字符会被替换为 < 和 > 。这样可防止攻击者经过在表单中注入 HTML 或 JavaScript 代码(跨站点脚本攻击)对代码进行利用。*/ return $data; } ?> <h2>PHP 验证明例</h2> <form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>"> 姓名:<input type="text" name="name"> <br><br> 电邮:<input type="text" name="email"> <br><br> 网址:<input type="text" name="website"> <br><br> 评论:<textarea name="comment" rows="5" cols="40"></textarea> <br><br> 性别: <input type="radio" name="gender" value="female">女性 <input type="radio" name="gender" value="male">男性 <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>
到这一步,实现了表单到PHP提交,可是并无实现验证。html
2.设置必填字段:web
<?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"])) {//经过empty()来检查变量是否为空 $nameErr = "Name is required"; } else { $name = test_input($_POST["name"]); } if (empty($_POST["email"])) { $emailErr = "Email is required"; } else { $email = test_input($_POST["email"]); } if (empty($_POST["website"])) { $website = ""; } else { $website = test_input($_POST["website"]); } 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"]); } } ?>
显示错误信息:正则表达式
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>"> Name: <input type="text" name="name"> <span class="error">* <?php echo $nameErr;?></span> <br><br> E-mail: <input type="text" name="email"> <span class="error">* <?php echo $emailErr;?></span> <br><br> Website: <input type="text" name="website"> <span class="error"><?php echo $websiteErr;?></span> <br><br> <label>Comment: <textarea name="comment" rows="5" cols="40"></textarea> <br><br> Gender: <input type="radio" name="gender" value="female">Female <input type="radio" name="gender" value="male">Male <span class="error">* <?php echo $genderErr;?></span> <br><br> <input type="submit" name="submit" value="Submit"> </form>
3.验证名字、URL和邮箱的格式,正则表达式函数
<?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(此正则表达式一样容许 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"]); } } ?>
4.在用户提交表单后保留表单中的值post
Name: <input type="text" name="name" value="<?php echo $name;?>"> E-mail: <input type="text" name="email" value="<?php echo $email;?>"> Website: <input type="text" name="website" value="<?php echo $website;?>"> Comment: <textarea name="comment" rows="5" cols="40"><?php echo $comment;?></textarea> Gender: <input type="radio" name="gender" <?php if (isset($gender) && $gender=="female") echo "checked";?> value="female">Female <input type="radio" name="gender" <?php if (isset($gender) && $gender=="male") echo "checked";?> value="male">Male
isset()函数用于判断变量是否已经配置。ui