h1>用戶注冊/h1>
  form method="post" action="register_verify.php">
    input type="text" placeholder="用戶名" name="username">br>br>
    input type="password" placeholder="密碼" name="password">br>br>
    input type="password" placeholder="重復密碼" name="password2">br>br>
    label>性別：
      input type="radio" name="sex" value="男" checked="checked">男
      input type="radio" name="sex" value="女">女/label>br>br>
    input type="email" placeholder="郵箱" name="email">br>br>
    button class="btn" type="submit">注冊/button>
  /form>

?php
require "mysql.php";      //導入mysql.php訪問數據庫
$username=$_POST['username'];
$password=$_POST['password'];
$password2=$_POST['password2'];
$sex=$_POST['sex'];
$email=$_POST['email'];
if(checkEmpty($username,$password,$password2,$sex,$email)){
  if(checkpwd($password,$password2)){
    if(checkEmail($email)){
      if(insert($username,$password,$sex,$email))
        echo"注冊成功";
    }
  }
}
//方法：判斷是否為空
function checkEmpty($username,$password,$password2,$sex,$email){
  if($username==null||$password==null||$password2==null){
    echo 'html>head>Script Language="JavaScript">alert("用戶名或密碼為空");/Script>/head>/html>'       . "meta http-equiv=\"refresh\" content=\"0;url=register.html\">";
  }
  else{
    if($sex==null){
      echo 'html>head>Script Language="JavaScript">alert("性別為空");/Script>/head>/html>' .          "meta http-equiv=\"refresh\" content=\"0;url=register.html\">";
    }
    elseif($email==null){
      echo 'html>head>Script Language="JavaScript">alert("郵箱為空");/Script>/head>/html>' .          "meta http-equiv=\"refresh\" content=\"0;url=register.html\">";
    }
    else{
      return true;
    }
  }
}
//方法：檢查兩次密碼是否相同
function checkpwd($password,$password2){
  if($password==$password2)
    return true;
  else
    echo 'html>head>Script Language="JavaScript">alert("兩次密碼不一致");/Script>/head>/html>' .        "meta http-equiv=\"refresh\" content=\"0;url=register.html\">";
}
//方法：郵箱格式驗證
function checkEmail($email){
  $preg = '/^(\w{1,25})@(\w{1,16})(\.(\w{1,4})){1,3}$/';
  if(preg_match($preg, $email)){
    return true;
  }else{
    echo 'html>head>Script Language="JavaScript">alert("郵箱格式有誤");/Script>/head>/html>' .        "meta http-equiv=\"refresh\" content=\"0;url=register.html\">";
  }
}
//方法：將數據插入數據庫中
function insert($username,$password,$sex,$email){
  $conn=new Mysql();
  $sql="insert into user VALUE (null,'$username','$password','$sex','$email')";
  $result=$conn->sql($sql);
  if($result){
    return true;
  }
  else{
    echo 'html>head>Script Language="JavaScript">alert("寫入數據庫失敗");/Script>/head>/html>' .        "meta http-equiv=\"refresh\" content=\"0;url=register.html\">";
  }
  $conn->close();
}