if (screen.width == 800) {
  document.write('<link rel="stylesheet" type="text/css" href="includes/website800.css">');
}else if (screen.width == 1024) {
  document.write('<link rel="stylesheet" type="text/css" href="includes/website1024.css">');
}else if (screen.width == 1280)  {
  document.write('<link rel="stylesheet" type="text/css" href="includes/website1280.css">');
}else if (screen.width == 1440) {
  document.write('<link rel="stylesheet" type="text/css" href="includes/website1440.css">');
}else{
  document.write('<link rel="stylesheet" type="text/css" href="includes/website1440.css">');
}