function trim(s)
{
  while (s.substring(0,1) == ' ')
  {
    s = s.substring(1,s.length);
  }
  while (s.substring(s.length-1,s.length) == ' ')
  {
    s = s.substring(0,s.length-1);
  }
  return s;
}

function $(id)
{
   return document.getElementById(id);
}

// tworzy nowy element
function elem(name, attrs, style, text)
{
   var e = document.createElement(name);
   if (attrs) {
       for (key in attrs) {
           if (key == 'class') {
               e.className = attrs[key];
           } else if (key == 'id') {
               e.id = attrs[key];
           } else {
               e.setAttribute(key, attrs[key]);
           }
       }
   }
   if (style) {
       for (key in style) {
           e.style[key] = style[key];
       }
   }
   if (text) {
       e.appendChild(document.createTextNode(text));
   }
   return e;
}

function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}