php之form表单

<!DOCTYPE HTML>
<html>
    <head>
        <title>form</title>
        <style type="text/css">
            .err{
                color: red;
            }
        </style>
    </head>
    <body>
        <?php
            $name = $email = $website = $commet = $gender = $nameErr = $emailErr = $genderErr = '';
            if($_SERVER['REQUEST_METHOD'] == "POST"){
                if(empty($_POST['name'])){
                    $nameErr = "姓名为必填项";
                }else{
                    $name = test_input($_POST['name']);
                    if(!preg_match("/^[a-zA-Z ]*$/" , $name)){
                        $nameErr = "姓名只允许字母和空格";
                    }
                }

                if(empty($_POST['email'])){
                    $emailErr = "邮件为必填项";
                }else{
                    $email = test_input($_POST['email']);
                    if(!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/" , $email)){
                        $emailErr = "邮件格式不正确";
                    }
                }

                if(empty($_POST['gender'])){
                    $genderErr = "性别为必选项";
                }else{
                    $gender = test_input($_POST['gender']);
                }

                $website = empty($_POST['website'])?'':test_input($_POST['website']);
                $commet = empty($_POST['commet'])?'':test_input($_POST['commet']);
            }

            function test_input($str){
                $str = trim($str);
                $str = stripslashes($str);
                $str = htmlspecialchars($str);
                return $str;
            }
        ?>
        <form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']); ?>" method="post">
            <p>姓名：<input type="text" name="name" value="<?php echo $name;?>"/><span class="err">* <?php echo $nameErr; ?> </span></p>
            <p>邮件：<input type="text" name="email" value="<?php echo $email;?>" /><span class="err">* <?php echo $emailErr; ?></span></p>
            <p>网址：<input type="text" name="website" value="<?php echo $website;?>"/></p>
            <p>评论：<textarea name="commet" id="" cols="30" rows="10"><?php echo $commet;?></textarea></p>
            <p>性别
                <label><input type="radio" name="gender" value="female" <?php if(isset($gender) && $gender=="female") echo 'checked'; ?>/>女性</label>
                <label><input type="radio" name="gender" value="male" <?php if(isset($gender) && $gender == 'male') echo 'checked'?>/>男性</label>
                <span class="err">* <?php echo $genderErr; ?></span>
            </p>
            <button>提交</button>
        </form>
        <hr />
        <?php echo $name;?>
        <br />
        <?php echo $email;?>
        <br />
        <?php echo $website;?>
        <br />
        <?php echo $commet;?>
        <br />
        <?php echo $gender;?>
    </body>
</html>
<?php

?>