我在ajax中编写了以下代码，向后端发送了一个请求

$.ajax({
      type: "POST",url: action,data: str,success: function(msg) {
        //alert(msg);

        if (msg == 'sent') {
            alert("success");
          $('#errormessage').html('<div class="alert alert-success">Email sent successfully.</div>');
          $('.contactForm').find("input,textarea").val("");
        }else if (msg == 'saved') {
          $("#sendmessage").removeclass("show");
          $("#errormessage").addClass("show");
          $('#errormessage').html('<div class="alert alert-warning">Email couldn\'t be sent but not too worry we got it in our database. We will get back to you.</div>');
          $('.contactForm').find("input,textarea").val("");
        }

         else {
          $("#sendmessage").removeclass("show");
          $("#errormessage").addClass("show");
          $('#errormessage').html(msg);
        }

      }
    });

php代码

$to_email = $set['Email'];

$headers = "From: ". $email;

//check if the email address is invalid $secure_check
$secure_check = sanitize_my_email($email);
if ($secure_check == false) {
    echo "Invalid input";
} else { //send email 
$query = mysqli_query($mysqli,"INSERT INTO emails(name,email,subject,message)VALUES('$name','$email','$sub','$msg')");
$mail = mail($to_email,$sub,$msg,$headers);

if($query and $mail){
    echo 'sent';
}else if($query and  !$mail){
    echo 'saved';
}else{
    echo $mysqli->error;
}

}

如果我发送电子邮件，则插入成功执行。我面临的问题是ajax无法打印正确的消息。它只执行显示已发送

这部分代码不正确：

if (msg == 'sent') {
        alert("success");
      $('#errormessage').html('<div class="alert alert-success">Email sent successfully.   
       </div>');
      $('.contactForm').find("input,textarea").val("");
       }

相反，它仅显示已发送消息

else {
          $("#sendmessage").removeclass("show");
          $("#errormessage").addClass("show");
          $('#errormessage').html(msg);
        }