在javascript结果之前有很多空格

我有一个登录脚本，应该分别返回"成功"或"失败"，但它在结果之前添加了很多空格，在控制台中它将值显示为"<吨空间>成功"。这是登录脚本的 PHP：

public function login() {
    global $dbc, $layout;
    if(!isset($_SESSION['uid'])){
        if(isset($_POST['submit'])){
            $username = mysqli_real_escape_string($dbc, trim($_POST['email']));
            $password = mysqli_real_escape_string($dbc, trim($_POST['password']));
            if(!empty($username) && !empty($password)){
                $query = "SELECT uid, email, username, password, hash FROM users WHERE email = '$username' AND password = SHA('$password') AND activated = '1'";
                $data = mysqli_query($dbc, $query);
                if((mysqli_num_rows($data) === 1)){
                    $row = mysqli_fetch_array($data);
                    $_SESSION['uid'] = $row['uid'];
                    $_SESSION['username'] = $row['username'];
                    $_SERVER['REMOTE_ADDR'] = isset($_SERVER["HTTP_CF_CONNECTING_IP"]) ? $_SERVER["HTTP_CF_CONNECTING_IP"] : $_SERVER["REMOTE_ADDR"];
                    $ip = $_SERVER['REMOTE_ADDR'];
                    $user = $row['uid'];
                    $query = "UPDATE users SET ip = '$ip' WHERE uid = '$user' ";
                    mysqli_query($dbc, $query);
                    setcookie("ID", $row['uid'], time()+3600*24);
                    setcookie("IP", $ip, time()+3600*24);
                    setcookie("HASH", $row['hash'], time()+3600*24);
                    echo 'success';
                    exit();
                } else {
                    //$error = '<div class="shadowbar">It seems we have run into a problem... Either your username or password are incorrect or you haven''t activated your account yet.</div>' ;
                    //return $error;
                $err = 'failure';
                echo($err);
                exit();
                }
            } else {
                //$error = '<div class="shadowbar">You must enter both your username AND password.</div>';
                //return $error;
                $err = "{'"result'":'"failure'"}";
                echo json_encode($err);
                exit();
            }
        }
    } else {
        echo '{"result":"success"}';
        exit();
    }
    return $error;
}

以及表单和 JS

    <div class="shadowbar"><form id="login" method="post" action="/doLogin">
    <div id="alert"></div>
    <fieldset>
     <legend>Log In</legend>
    <div class="input-group">
      <span class="input-group-addon">E-Mail</span>
      <input type="email" class="form-control" name="email" value="" /><br />
    </div>
    <div class="input-group">
      <span class="input-group-addon">Password</span>
      <input type="password" class="form-control" name="password" />
      </div>
    </fieldset>
    <input type="submit"  class="btn btn-primary" value="Log In" name="submit" />
    </form></div>

$(function login() {
    $("#login").validate({ // initialize the plugin
        // any other options,
        onkeyup: false,
        rules: {
            email: {
                required: true,
                email: true
            },
            password: {
                required: true
            }
        }
    });
    $('form').ajaxForm({
        beforeSend: function() {
            return $("#login").valid();
        },
                success : function(result) {
                    console.log(result);
                    if(result == " success"){
                        window.location = "/index.php";
                    }else if(result == " failure"){
                        $("#alert").html("<div class='alert alert-warning'>Either you're username or password are incorrect, or you've not activated your account.</div>");
                        //$("#alert").show();
                    }
               }
    });
}); 

但是由于某种原因，结果总是有很多空间。我是 JS 的新手，所以如果这很常见，我还不知道。

<?php
    error_reporting(E_ALL); ini_set('display_errors', 1);
    define("CCore", true);
    session_start();
    //Load files...
    require_once('include/scripts/settings.php');
    require_once('include/scripts/version.php');
    require('include/scripts/core.class.php');
    require('include/scripts/nbbc_main.php'); 
    $parser = new BBCode;
    $core = new core;
    $admin = new admin;
    require_once('include/scripts/layout.php');
    require_once('include/scripts/page.php');
    //Set Variables...
    global $dbc, $parser, $layout, $main, $settings, $core;
    $page = new pageGeneration;
    $page->Generate();

?>

这是我的索引，在生成页面并调用 login（） 之前的任何内容都在那里。