In this website, I want to load my pages with JQuery and Ajax by clicking on a menue point.

The problem is, that I have errors by loading it.
What does the Error "GET 'path to css file'" in the console mean?
(there is some Ajax code by clicking on error)

It seems that the browser doesn't load the whole css file in the content.
I hope that you can help me, because I don't now what could be wrong.

Here is my code:

JQuery/Ajax:

$(document).ready(function(){

 $("menue li > a").click(function(){
   var hash = this.hash.substr(1);

    if(hash){
      console.log(hash);
      $(document.body).load("js/sv_index.php",  {id:hash});
  }
 });
});

PHP

<?php
  $id = $_POST['id'];

  switch($id){
    case ("index"):
        include '../index.php';
        break;

    case("tutorials"):
        include '../php/tutorials.php';
        break;

    case("news"):
        include '../php/news.php';
        break;

    case("terminal"):
        include '../php/terminal.php';
        break;

    case("anmeldung"):
        include '../php/anmeldung.php';
        break;
  }
?>