function get_categories() {
  $.ajax({
    type: "GET",
    url: 'assets/php/get_categories.php',
    success: function(data) {
      $.each(JSON.parse(data), function(i, category) {
        cat = category.replace('_', ' ').toUpperCase();
        $('#categories').append(`<li><a href='./?cat=${category}&catpage=1'>${cat}</a></li>`);
      });
    },
    error: function(error) {
      console.log(error);
    }
  });
}