PHP - 在循环中向AJAX / JQuery发送一个值

Question

我遇到问题，只将一个echo = 'true_user'发送回jquery。现在，true_user将根据用户选择的$id发送回jquery。

其次，如何将echo ='false'和echo ='failed'发送回jquery时如何组合？我尝试使用||但仍然无法正常工作。

jQuery / AJAX

<script>
  jQuery(document).ready(function(){
    jQuery("#delete_user").submit(function(e){
      e.preventDefault();
      var formData = jQuery(this).serialize();
      $.ajax({
        type: "POST",
        url: "delete_users.php",
        data: formData,
        success: function(html){

          if (html=='false_user'){
            $.jGrowl("Please select user", { header: 'Error' });
            alert(html);
          }else if (html=='failed'){
            $.jGrowl("Cannot delete your own account", { header: 'Account Protected' });  
            alert(html);
            var delay = 1000;
            setTimeout(function(){ window.location = 'admin_user.php'  }, delay);   
          }else if(html=='true'){
            $.jGrowl("Loading Please Wait......", { sticky: true });
            $.jGrowl("Successfully Deleted", { header: 'User Deleted' });
            alert(html);
            var delay = 1000;
            setTimeout(function(){ window.location = 'admin_user.php'  }, delay); 
          }else if (html=='true_user'){ 
            $.jGrowl("Loading Please Wait......", { sticky: true });
            $.jGrowl("Successfully Deleted", { header: 'Users Deleted' });
            alert(html);
            var delay = 1000;
            setTimeout(function(){ window.location = 'admin_user.php'  }, delay);  
          }else if (html=='false','failed'){
            $.jGrowl("Cannot delete your own account", { header: 'Account Protected' });  
            alert(html);
            var delay = 1000;
            setTimeout(function(){ window.location = 'admin_user.php'  }, delay);         
          }else{
            $.jGrowl("Please try again", { header: 'Error' });
            alert(html);
            var delay = 1000;
            setTimeout(function(){ window.location = 'admin_user.php'  }, delay); 
          }

        }//success
      });
      return false;
    });
  });
</script>

delete_users.php

<?php
error_reporting(E_ALL&~E_NOTICE);
include('dbcon.php');
include('session.php');
//if (isset($_POST['delete_user'])){
$id=$_POST['selector'];
//$id = array(61);
$N = count($id);

if ($N == 0){ //if no selected
    echo 'false_user';
} else { //if selected

    for($i=0; $i < $N; $i++)
    {   

        $stmt = $conn->prepare("select * from users WHERE user_id=:id");
        $stmt->bindParam(':id',$id[$i]);
        $stmt->execute();
        $result = $stmt->fetchObject();
        $userType = $result->user_type;

        //$user_type = $row['user_type']

        if ($userType >= 1){ //if user type not 0 = developer

            if  ($id[$i] == $session_id){ // cannot delete own account
                echo 'failed';
            } else if($N==1){
                $stmt = $conn->prepare("DELETE FROM users where user_id=:id");

                $stmt->bindParam(':id',$id[$i]);
                $stmt->execute();
                $stmt->rowCount();
                echo 'true';
            } else if ($N > 1){ // if select more than one

                $stmt = $conn->prepare("DELETE FROM users where user_id=:id");

                $stmt->bindParam(':id',$id[$i]);
                $stmt->execute();
                $stmt->rowCount();
                $testing = 'true_user';
                //return;
            }
        }else{ //other error

            echo 'false';
        }
    }
}

?>