Event.onReady(function(){
  var c = document.cookie.split(";");
  $A(c).each(function(cookie){
    if (cookie.split("=")[0] == "fontSize")
    {
      fsize(cookie.split("=")[1]);
    }
  });
});

function fsize(size){
  $$("body").each(function(e) {
    e.className = e.className.replace(/defaultText|mediumText|largeText/g,"");
    e.className += (" " + size + "Text");
    document.cookie = "fontSize=" + size;
  });
}