function swapStyle( n, dontWrite ) {

   if (!dontWrite) setCookie( "style", n, 10 );

   var links = document.getElementsByTagName('link');
   for ( var i = 0; i < links.length; i++ ) {
      var title = links[i].getAttribute("title");
      if ( title == "Simple" || title == "Ciel et mer" || title == "Mozilla" || title == "Matrix" || title == "LCars") {
         if (i == n) {
            links[i].disabled = false;
         } else {
            links[i].disabled = true;
         }
      }
   }
}

function loadStyle() {
   var ual = navigator.userAgent.toLowerCase();
   var is_gecko = (ual.indexOf("gecko") != -1);
   
   // Show the options
   if ( is_gecko ) {
      var style = getCookie( "style" );
      var ss = document.getElementById('stylesheets');
      if (ss) {
         ss.style.display = "block";
      }
      if ( style ) {
         swapStyle( style, true );
      }
   }
}

function setCookie(name, value, days) {
   var expireDate = new Date ();
   expireDate.setTime( expireDate.getTime() + (days * 24 * 3600 * 1000) );

   document.cookie = name + "=" + escape(value) + "; expires=" + expireDate.toGMTString();
}

function getCookie(name) {
   if (document.cookie.length > 0) {
      var start;
      var end;

      start = document.cookie.indexOf(name + "=");
      if ( start == -1 ) return null;
      end = document.cookie.indexOf(";", start);
      if (end == -1) end = document.cookie.length;

      return unescape( document.cookie.substring(start + name.length + 1, end) );
   }
   return null; 
}

function deleteCookie( name ) {
   if ( getCookie(name) ) {
      document.cookie = name + "=" + "; expires=Thu, 01-Jan-70 00:00:01 GMT";
   }
}