javascript - echo 正在向我在 PHP 中输​​出的内容添加新行

Question

我正在发送回显一些要在 Javascript 中接收的数据，但是当我调试它时，似乎添加了一个新行。

PHP

<?php
header("Content-Type: application/json; charset=UTF-8");
require './connection.php';

$obj = json_decode($_POST["x"], false);

$usernamequery = "SELECT * FROM User WHERE username='$obj->newUser'";

$result = mysqli_query($db, $usernamequery);
$row = mysqli_fetch_assoc($result);

if($row["Username"] == null){

    $updatequery = "UPDATE User SET User='$obj->newUser' WHERE username ='$obj->username'";
    $result = mysqli_query($db, $updatequery);

    echo "valid";
} else{
    echo "invalid";
}

?>

JS

///// USERNAME
$(document).ready(function () {

$("#userSubmitForm").on("click", function(e) {

   $username = document.getElementById("user").value;
   $newUser = document.getElementById("newUser").value;
   user = $newUser;
   obj = { "username":$username, "newUser":$newUser};
   dbParam = JSON.stringify(obj);

   xmlhttp = new XMLHttpRequest();
   xmlhttp.onreadystatechange = function() {
   if (this.readyState === 4 && this.status === 200) {
    validity = this.responseText;

    if (validity === "valid"){
            $('#usernameModal .modal-header .modal-title').html("Result");
            $('#usernameModal .modal-body').html("Your Username Has Been Changed to '$newUser'");
            $("#passSubmitForm").remove(); 
            $("#userCloseForm").remove();

            window.setTimeout(redirect,3000);
    } else{

   $('#error').html("This Username Already Exists"); ;
          } 
    }
 };

发生的情况是responseText将被接收为“valid[newline]”/“invalid[newline]”，“valid”/“Invalid”

Answer 1

如http://php.net/manual/en/function.echo.php所述这不可能是 echo 的“问题”。 -标签后必须有一些换行符