// thank you to http://www.quirksmode.org/js/cookies.html
function createCookie(name,value,minutes)
{
        if (minutes)
        {
                var date = new Date();
                date.setTime(date.getTime()+(minutes*60*1000));
                var expires = "; expires="+date.toGMTString();
        }
        else var expires = "";
        document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name)
{
        var nameEQ = name + "=";
        var ca = document.cookie.split(';');
        for(var i=0;i < ca.length;i++)
        {
                var c = ca[i];
                while (c.charAt(0)==' ') c = c.substring(1,c.length);
                if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
        }
        return null;
}

function eraseCookie(name)
{
        createCookie(name,"",-1);
}

// requires prototype!
function removeElementsByClassName(className) {
  var holders = document.getElementsByClassName(className);
  for (var i = holders.length-1; i >= 0; i--) {
    Element.remove(holders[i]);
  }
}