var CSSCookieName = "nb-style" ;
var CSSCookieDuration = 30 ;

function switchCSS ( CSSTitle )
{
  var i, link_tag ;
  for (i = 0, link_tag = document.getElementsByTagName("link") ;
    i < link_tag.length ; i++ ) {
    if ((link_tag[i].rel.indexOf( "stylesheet" ) != -1) && link_tag[i].title) {
      link_tag[i].disabled = true ;
      if (link_tag[i].title == CSSTitle ) {
        link_tag[i].disabled = false ;
      }
    }
    createCookie ( CSSCookieName, CSSTitle, CSSCookieDuration );
  }
}

function setCSS()
{
  var CSSTitle = readCookie ( CSSCookieName );
  if (CSSTitle.length) {
    switchCSS( CSSTitle );
  }
}

function createCookie ( cookieName, cookieValue, cookieDuration, domainLevel )
{
  if (cookieDuration) {
    var date = new Date();
    date.setTime(date.getTime()+(cookieDuration*24*60*60*1000));
    var expires = "; expires="+date.toGMTString();
  }
  else expires = "";
  document.cookie = cookieName+"="+cookieValue+expires+"; path=/";
}

function readCookie ( cookieName )
{
  var nameEQ = cookieName  + "=";
  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;
}