function changeObjectVisibility(id){
  var expandable = $(id)
  if (expandable.style.display != "block")
    expandable.style.display = "block";
  else
    expandable.style.display = "none";
}

function setFieldHint(fieldID, hint) {
  var field = $(fieldID);
  field['hint_value'] = hint;
  field.value = hint;
  field.onfocus = function(){
    if (this.value == this['hint_value'])
      this.value="";
  }
  field.onblur = function() {
    if (this.value == "")
      this.value = this['hint_value'];
  }
}