function change_main_pict(filename){
  // Get element with main_pict id
  mp = document.getElementById("main_pict");

  // Change the source with the filename provided
  mp.src = "./photos/" + filename;
}

function change_category(sales){
  // Get select with category_selection id
  sel = document.getElementById("category_selection");
  
  // Get value of the category selected
  cat = sel.value;

  // Update content
  updateContent("./photos.php?category=" + cat + sales);
}