function obj_on(obj){
  if (document.getElementById(obj)) {
    el = document.getElementById(obj)
    el.style.display = 'block'
  }
}
function obj_off(obj){
  if (document.getElementById(obj)) {
    el = document.getElementById(obj)
    el.style.display = 'none'
  }
}
function obj_swap(obj){
  if (document.getElementById(obj)) {
    el = document.getElementById(obj)
    if(el.style.display == 'none' || el.style.display == ''){
      el.style.display = 'block'
    } else {
      el.style.display = 'none'
    }
  }
}