document.body.className = "fondo1"; 

function SetCookie(sName, sValue){
  var date = new Date(2010,11,31);
  document.cookie = sName + "=" + escape(sValue) + "; expires=" + date.toGMTString();
}

function GetCookie(sName){
  var aCookie = document.cookie.split("; ");
  for (var i=0; i < aCookie.length; i++){
    var aCrumb = aCookie[i].split("=");
    if (sName == aCrumb[0]) 
	  return unescape(aCrumb[1]);
  }
  return null;
}

function DelCookie(sName){
  document.cookie = sName + "=" + escape(sValue) + "; expires=Fri, 31 Dec 1999 23:59:59 GMT;";
}


function setBackground(colorFondo)
{
   document.body.className = colorFondo;
   SetCookie("colorFondo", colorFondo);
}     

function ComprobarFondo()
{
    var colorFondo = GetCookie("colorFondo");
    if(colorFondo!=null)
    document.body.className = colorFondo; 
}