Javascript 在执行PHP脚本后使按钮可见

大家好，我有一个要求，让一个添加项目按钮可见，一旦用户登录im试图测试与下面的测试代码这一点，但不知道最好的方法，使一个php调用后，任何帮助按钮可见将不胜感激

passwordchecker.php

<?php
        $message = "access granted, you can now add items";
        $message1 = "access denied";
    $user = $_POST['username'];
        $pass = $_POST['password'];
        if ($user == "admin" && $pass == "admin")
        {
        echo "<script type='text/javascript'>
          alert('$message');
          </script>";
        die();
        }
        else
        {
         echo "<script type='text/javascript'>
          alert('$message1');
          </script>";
              die();
        }
?>

---

首先使用会话变量检查身份验证。
基本上，无需任何javascript即可完成此操作
简单地

在登录或您想要的地方设置$\u SESSION['user']后，只需像这样将其添加到PHP中（如果用户存在，则回显按钮，否则不要）


<a href="#AddItems" class="btn btn-default btn-lg history" style="visibility:hidden" id="additems">Add item</a>

if ($user == "admin" && $pass == "admin") 
    { 
       ?>
        <a href="#AddItems" class="btn btn-default btn-lg history" style="visibility:hidden" id="additems">Add item</a>
      <?php
      }

<?php 
    if ($user == "admin" && $pass == "admin") 
        { 
         ?>
           <script>
               $( document ).ready(function() {
                  $('#additems').show();
                  alert(<?php echo $message;?>); 
               });
            </script>
          <?php
          } else {
              <script>
               $( document ).ready(function() {
                  alert(<?php echo $message1;?>); 
               });
            </script>
          }

if (isset($_SESSION['user'])) instead of if ($user == "admin" && $pass == "admin")

<?php
    $message = "access granted, you can now add items";
    $message1 = "access denied";
    $user = $_POST['username'];
    $pass = $_POST['password'];
    if ($user == "admin" && $pass == "admin")
    {
    echo "<script type='text/javascript'>
      alert('$message');
      </script>'
      <a href=\"#AddItems\" class=\"btn btn-default btn-lg history\" style=\"visibility:hidden\" id=\"additems\">Add item</a>";
    die();
    }
    else
    {
     echo "<script type='text/javascript'>
      alert('$message1');
      </script>";
          die();
    }
?>