$(document).ready(function() {
    var css_title = get_cookie(style_cookie_name);
    if (css_title.length) {
        switch_style(css_title);
    }
});

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

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_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] ) ;*/

        var cookie_value = cookie_string.substring(cookie_string.indexOf("style=") + 6);
        if (cookie_value == null) {
            cookie_value = "grey";
        }
        return cookie_value;
    }
    return '' ;
}