// *** TO BE CUSTOMISED ***

var style_cookie_name     = "style";
var style_cookie_duration = 30;

// *** END OF CUSTOMISABLE SECTION ***

function switch_style ( css_title ) {
  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 == css_title) {
        link_tag[i].disabled = false ;
      }
    }
    set_cookie( style_cookie_name, css_title, style_cookie_duration );
  }
}

function set_style_from_cookie() {
  var css_title = get_cookie( style_cookie_name );
  if (css_title.length) {
    switch_style( css_title );
  }
}

function set_cookie ( cookie_name, cookie_value, lifespan_in_days, valid_domain ) {
    var domain_string = valid_domain ?
                       ("; domain=" + valid_domain) : '' ;
    document.cookie = cookie_name + "=" + encodeURIComponent( cookie_value ) + "; max-age=" + 60 * 60 * 24 * lifespan_in_days + "; path=/" + domain_string;
}

function get_cookie ( cookie_name ) {
    var cookie_string = document.cookie ;
    if (cookie_string.length != 0) {
        var cookie_value = cookie_string.match ('(^|;)[\s]*' + cookie_name + '=([^;]*)');
        return decodeURIComponent (cookie_value[2]) ;
    }
    return '' ;
}