I have this problem when I request to a php file using $.ajax it always return me a 500 server error, but only when I upload the files to my server.
I use XAMPP on Windows 8.1 and in the localhost runs perfectly.
I've tried accesing the url of the php file directly and also gives me the same error.
Ajax:
function get_blog(reload_list){
    var $titulo, $texto, $response, $post, $post_list;
    var parameters = window.location.search;
    $.ajax({
        method: 'get',
        url: '/php/blog.php' + parameters,
        success: function(data){
            if(data == "404"){
                $("#blog").html("404 El articulo que buscas no existe");
            } else {
                $response = data;
                $post_list = $response.post_list;
                $titulo = $response.post.titulo;
                $texto =  $response.post.texto;
                $("title#blog_title").html("IBR - " + $titulo);
                $("h3#blog_title").html($titulo);
                $("#blog_text").html($texto);
                if(reload_list){
                    for(i=0; i<=$post_list.length; i++){
                        $("#post_list").append($post_list[i]);
                    }
                }
            }
        }
    });
PHP:
<?php
error_reporting(E_ALL);
ini_set('display_errors' 1); 
$l =  mysql_connect ( "localhost" , "myserver" , "mypass" ) or die("Error connecting:<BR><BR>".mysql_error());
mysql_select_db( "mydb" ) or die("Error getting db:<BR><BR>".mysql_error()); 
if(!isset($_GET['post_id'])) {
    $query = mysql_query("SELECT * FROM mytable ORDER BY id DESC LIMIT 1") or die(mysql_error());
    $row = mysql_fetch_array($query);
    $id = stripslashes($row['id']); 
    $titulo = stripslashes($row['titulo']); 
    $texto = stripslashes($row['texto']); 
    $post = [
            'id' => $id,
            'titulo' => $titulo,
            'texto' => $texto
    ];
}else{
    // echo $_GET['post_id'];
    $post_id = $_GET['post_id'];
    $query = mysql_query("SELECT * FROM mytable WHERE id=$post_id ORDER BY id DESC LIMIT 1") or die(mysql_error());
    $row = mysql_fetch_array($query);
    if(empty($row)){
        die("404");
    }
    $id = stripslashes($row['id']); 
    $titulo = stripslashes($row['titulo']); 
    $texto = stripslashes($row['texto']); 
    $post = [
            'id' => $id,
            'titulo' => $titulo,
            'texto' => $texto
    ];
}
$query = mysql_query("SELECT * FROM mytable ORDER BY id DESC") or die(mysql_error());
while ($row = mysql_fetch_array($query) )
{
    $id = stripslashes($row['id']); 
    $titulo = stripslashes($row['titulo']); 
    $li = '<a class="text_decoration post_list_item" href="devocional.html?post_id='.$id.'"><li>'.$titulo.'</li></a>';
    $post_list[]= $li;
}
$response = [
    'post' => $post,
    'post_list' => $post_list
];
$json_response = json_encode($response);
print_r($json_response);
?>
Actually I don´t have access to my error_log. Also tried to see errors through the:
error_reporting(E_ALL);
ini_set('display_errors' 1);
But the browser only shows a blank page. I have this same issue on a Facebook API call using the PHP SDK too. I really don't know what to do. Thanks for helping in advance. 
 
     
    