Php Ajax响应格式

我的网站有一个用户注册，点击注册按钮时会执行一个ajax请求。此请求处理验证以及将用户添加到数据库。我有一切工作，但我有一个小问题，我想解决。在我的错误处理中，响应可能返回一个400 http状态代码，其中包含一个缺少的字段或无效的字段消息。对于这些消息，我希望在一行中显示换行符之前的句子，然后在新行中显示换行符之后的句子

PHP:

// If all the previous steps are valid and variables are set, try to run the SQL query to make new account.
if (isset($firstname) && isset($surname) && isset($email) && isset($usernameSignup) && isset($passwordHash)) {
    try {
        // code to add user to database not included but is here
    } catch (PDOException $e) {
        http_response_code(400);
        die("Email or Username Already Exists.\n Make sure these fields are valid before trying again.");
    }
} else {
    http_response_code(400);
    die("Missing Field(s).\n Make sure there are no empty fields before trying again.");
}

$.ajax({
    type: "post",
    url: "userRegistration.php",
    data: {
    },
    dataType: "json",
    success: function(xhr) {
      // Success handler code
      }
    },
    error: function(xhr) {
      // Default error handler code
    },
    statusCode: {
      400: function(res) {
        console.log(res);
        console.log(res.status);
        console.log(res.responseText);
        $("#loadingIcon").addClass("d-none");
        $("#errorResponse").removeClass("d-none");
        $("#errorMessage").text("An error occured: " + res.responseText);
      }
    }
});

JS:

// If all the previous steps are valid and variables are set, try to run the SQL query to make new account.
if (isset($firstname) && isset($surname) && isset($email) && isset($usernameSignup) && isset($passwordHash)) {
    try {
        // code to add user to database not included but is here
    } catch (PDOException $e) {
        http_response_code(400);
        die("Email or Username Already Exists.\n Make sure these fields are valid before trying again.");
    }
} else {
    http_response_code(400);
    die("Missing Field(s).\n Make sure there are no empty fields before trying again.");
}

$.ajax({
    type: "post",
    url: "userRegistration.php",
    data: {
    },
    dataType: "json",
    success: function(xhr) {
      // Success handler code
      }
    },
    error: function(xhr) {
      // Default error handler code
    },
    statusCode: {
      400: function(res) {
        console.log(res);
        console.log(res.status);
        console.log(res.responseText);
        $("#loadingIcon").addClass("d-none");
        $("#errorResponse").removeClass("d-none");
        $("#errorMessage").text("An error occured: " + res.responseText);
      }
    }
});

---

我希望“在重试之前确保没有空字段”位于新行。如果可能的话，我还希望以粗体显示“缺少的字段”

将html标记添加到文本中：

die("<b>Missing Field(s).</b><br /> Make sure there are no empty fields before trying again.");

die（“缺少字段）。
在重试之前，确保没有空字段。”；

然后更改您的js：

$("#errorMessage").html("An error occured:<br />" + res.responseText);

$（“#errorMessage”）.html（“发生错误：
”+res.responseText）；

您需要使用

html（）

函数，因为您的文本包含html标记