gistfile1.txt

<?php
  $name= $_POST['name'];  
  $query= "SELECT $name FROM markers; 
   $pdo=new PDO("mysql:dbname=markers;host=127.0.0.1","root","");
   $stmt = $pdo->query($query);
   $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
  json_encode($results);
?>

 $(function(){  
    $.ajax({                                      
      url: 'dbinfo.php', 
     data: {
            name: $nameFromMainSite,
        },
      dataType: 'json',                
      success: function(data)          
      {
        console.log(data);
      } 
   });   
});