如果不满足单个条件，如何阻止此代码运行PHP

Question

即使条件不满足，此代码仍会运行到最后并提交。我想阻止它运行并在错过任何条件时回显错误。请帮忙。注意：我已经尝试了exit（），它影响了整个html的运行。

  $verifiedPhone = phoneNumberValidator($phone);
    $correctsurname = nameValidator($surname);
    $correctlastname = nameValidator($lastname);
    $correctusername = nameValidator($username);
        if(!$verifiedPhone){
            echo "<p class='alert alert-warning'>Please use a Valid Phone Number</p>";

                            }
        if(!$correctsurname){
            echo "<p class='alert alert-warning'>Surname can only contain alphabets</p>";
                            }
        if(!$correctlastname) {
            echo "<p class='alert alert-warning'>Last Name can only contain alphabets</p>";
                            }
        if (!$correctusername) {
            echo "<p class='alert alert-warning'>Username can only contain alphabets</p>";
                            }
        $checkuser = "  SELECT * FROM staff
                        WHERE username = '$correctusername'";
        $checkuserresult = mysqli_query($connection, $checkuser);
        $checkuserrow = mysqli_num_rows($checkuserresult);
    if($checkuserrow > 0){
        echo "<p class='alert alert-danger'>Username \"".$username."\" already exist! Try another</p>";
                            }
  else{
        $harsedpassword = md5("$password");
  $datainsert = "   INSERT INTO staff (surname, lastname, phone, username, password) VALUES ('$correctsurname', '$correctlastname', '$verifiedPhone', '$username','$harsedpassword')";
 $datainsertresult = mysqli_query($connection, $datainsert);
  if($datainsertresult){
    echo "<p class='alert alert-success'><b>Staff Added Successfully</b></p>";
                                }

Answer 1

使用else ifs

if(!$correctsurname){
                        echo "<p class='alert alert-warning'>Surname can only contain alphabets</p>";
}
else if(!$correctlastname) {
                        echo "<p class='alert alert-warning'>Last Name can only contain alphabets</p>";
}
else if (!$correctusername) {
                        echo "<p class='alert alert-warning'>Username can only contain alphabets</p>";
}
else {
    //the rest

或者死亡（＆＃34;消息＆＃34;）如果你必须：

if(!$correctsurname){
                        die("<p class='alert alert-warning'>Surname can only contain alphabets</p>");     

}