function visible(id) {
 document.getElementById(id).style.visibility='visible';
}

function hidden(id) {
 document.getElementById(id).style.visibility='hidden';
}

function OnOff(id) {
 var id = document.getElementById(id);
 if(id.style.visibility=='visible')
  id.style.visibility='hidden';
 else
  id.style.visibility='visible';
}


function Preload(url) {
 if(!document.getElementById(url)){
  var id = document.getElementById('preload');
  if(id){
   var newDiv = document.createElement('div');
   newDiv.id = url;
   newDiv.innerHTML = '<img src="gallery/d'+url+'" />';
   id.appendChild(newDiv);
  }
 }
}