function show_div(id) {
  var menu = document.getElementsByClassName('popup_divs'); 
  for (i=0; i<menu.length; i++) {menu[i].style.display = 'none';}   
  $(id).style.display = 'block';
}

function hide_div() {
  var menu = document.getElementsByClassName('popup_divs'); 
  for (i=0; i<menu.length; i++) {menu[i].style.display = 'none';}
}