var PERIOD=30; //период обновления в секундах
var PREVIEW_URL='/m-cam.jpg'; //URL превью-картинки
var FULL_URL='/cam.jpg'; //URL полной картинки

var preview=false;
var full_container=false;
var full_image=false;
var init=function(){
  var body=document.body;
  var main=document.getElementById('main');
  if(body && main){
    var adv=main.nextSibling;
    var h3=document.createElement('H3');
    var p=document.createElement('P');
    preview=document.createElement('IMG');
    body.insertBefore(h3,adv);
    h3.innerHTML='Веб-камера';
    h3.style.clear='left';
    body.insertBefore(p,adv);
    p.style.marginBottom='2em';
    preview.title='Увеличить';
    preview.style.cursor='pointer';
    preview.onclick=showFull;
    p.appendChild(preview);
    full_container=document.createElement('P');
    full_container.style.display='none';
    full_container.style.position='absolute';
    full_container.style.zIndex='10';
    full_container.style.top='208px';
    full_container.style.left='267px';
    body.appendChild(full_container);
    full_image=document.createElement('IMG');
    full_image.title='Закрыть';
    full_image.style.cursor='pointer';
    full_image.onclick=hideFull;
    full_container.appendChild(full_image);
    rotate();
  }
}
if(window.addEventListener){
  window.addEventListener('load',init,false);
}else{
  window.attachEvent('onload',init);
}

var showFull=function(){
  full_container.style.display='';
  if(!full_image.src){
    full_image.src=FULL_URL;
  }
}
var hideFull=function(){
  full_container.style.display='none';
}
var rotate=function(){
  var ts=new Date().getTime();
  preview.src=PREVIEW_URL+'?'+ts;
  if(full_container && full_container.style.display==''){
    full_image.src=FULL_URL+'?'+ts;
  }
  setTimeout('rotate();',PERIOD*1000);
}