php用户验证后，查找用户id以授予用户一定的访问权限

我在一个站点中内置了一个登录表单，它使用PHP和JQuery进行验证。但是，我想在PHP或JQuery验证程序中添加一个内置函数，该函数将获取登录用户的用户id，并将其与同一数据库中的另一个表进行比较。另一个表中的数据将允许用户从特定于该用户的项目下拉列表中进行选择，最终控制用户在网站中看到的内容。这两个表是登录表和项目表。我想我需要从login表中获取user\u id，并与projects表中的user\u id进行比较，看看是否匹配。我不知道该怎么办

PHP:

JQuery：

  $("#login_validation").click(function(){
    var username=$('#user_name').val();
    var password=$('#password').val();
if(username===''){
      $("#add_err").html("*Please enter a user name.");
  return false;
}
else if(password===''){
  $("#add_err").html("*Please enter a password.");
  return false;
}
else{
  var loadTimeout = setTimeout(tick, 12100);
  $.ajax({
        type: "POST", 
    timeout:12000,
        url: "login_validation.php",
        data: "submit=true&user_name="+username+"&pwd="+password,
    beforeSend:function(){    
          $("#add_err").fadeIn("fast").html('<img src="image/loader.gif" />');
    },
        success: function(html){
      clearTimeout(loadTimeout);
      var html=trim(html);
      if(html=='true'){
            $("#login_b").fadeOut("normal");
    $("#login_b").promise().done(function(){
      $('#projects').css("display", "block");
        })
        //$('#profile').css("display", "block");
            //$("#profile").html("<a href='logout_session.php' id='logout'>Logout</a>");
          }          
          else{
            $("#add_err").html("*Wrong username or password");
          }
        }
      });//end ajax
      return false;
    }
  });//end #login_validation
  $("#project_validation").click(function(){
});
var tick = function(){
  $("#add_err").html('Unable to fetch page!');
}
function trim(str){
  var str=str.replace(/^\s+|\s+$/,'');
  return str;
}

表格：

---

我仍在学习JQuery和PHP，因此非常感谢在正确方向上的任何帮助

获取您正在检查的用户id

对表中允许用户id的位置运行查询，并将其分解为数组

然后检查您正在检查的用户id是否在该数组中

  $("#login_validation").click(function(){
    var username=$('#user_name').val();
    var password=$('#password').val();
if(username===''){
      $("#add_err").html("*Please enter a user name.");
  return false;
}
else if(password===''){
  $("#add_err").html("*Please enter a password.");
  return false;
}
else{
  var loadTimeout = setTimeout(tick, 12100);
  $.ajax({
        type: "POST", 
    timeout:12000,
        url: "login_validation.php",
        data: "submit=true&user_name="+username+"&pwd="+password,
    beforeSend:function(){    
          $("#add_err").fadeIn("fast").html('<img src="image/loader.gif" />');
    },
        success: function(html){
      clearTimeout(loadTimeout);
      var html=trim(html);
      if(html=='true'){
            $("#login_b").fadeOut("normal");
    $("#login_b").promise().done(function(){
      $('#projects').css("display", "block");
        })
        //$('#profile').css("display", "block");
            //$("#profile").html("<a href='logout_session.php' id='logout'>Logout</a>");
          }          
          else{
            $("#add_err").html("*Wrong username or password");
          }
        }
      });//end ajax
      return false;
    }
  });//end #login_validation
  $("#project_validation").click(function(){
});
var tick = function(){
  $("#add_err").html('Unable to fetch page!');
}
function trim(str){
  var str=str.replace(/^\s+|\s+$/,'');
  return str;
}

<fieldset id="login_form_wrap" class="login_form_header">
  <legend>CUSTOMER LOGIN</legend>
  <?php session_start(); ?> 
  <div id="profile">
<?php if((!isset($_SESSION['user_name'])) || ($_SESSION['timeout'] + 10 * 60 < time())){ ?>
  <div id="login_a">
    <a id="login_profile" href="#">click to login</a>
  </div>
<?php }else {;?>
  <a href='logout_session.php' id='logout'>Logout</a>
  <!-- header('location: dashboard.php'); -->
<?php } ?>
</div>
<form action="login_validation.php" id="login_form" method="POST">
  <div id="login_b">
    <div class="welcome"></div>
    <div class="wrapper">
      <span class="col1">USER NAME:</span>
      <input type="text" id="user_name" name="user_name" class="input" required />
    </div>
    <div class="wrapper">
      <span class="col1">PASSWORD:</span>
      <input type="password" id="password" name="password" class="input" required />
    </div>
    <div class="wrapper">
      <span class="col1"></span>
      <input type="submit" name"submit" id="login_validation" value="SUBMIT" />
      <input type="reset" id="cancel_hide" value="CANCEL" />
      <div class="err" id="add_err"><br></div>
      <div id="divMayus" style="visibility:hidden">Caps Lock is on.</div>
    </div>
  </div>
  <div id="projects">
  <div class="welcome">Welcome <?php echo $_SESSION['user_name']; ?></div>
    <div class="wrapper">
      <span class="col1">PROJECTS:</span>
      <select id="Projects" class="input">
        <option value="" selected="selected" disabled='disabled'>Choose a Project...</option>
        <?php
        // Loop through the query results, outputing the options one by one
        while ($row = mysql_fetch_array($query)) {
          echo '<option value="'.$row['projects'].'">'.$row['projects'].'</option>';
        }?>
      </select>  
    </div>
    <div class="wrapper">
      <span class="col1"></span>          
      <input type="submit" name"submit" id="project_validation" value="SELECT" />
      <div class="err" id="add_err"><br></div> 
    </div>
  </div>
</form>