/* http://www.alistapart.com/stories/alternate/ */

function setActiveStyleSheet(title) {
  var i, a, main;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title")) {
      a.disabled = true;
      if(a.getAttribute("title") == title) a.disabled = false;
    }
  }
}

function getActiveStyleSheet() {
  var i, a;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title") && !a.disabled) return a.getAttribute("title");
  }
  return null;
}

function getPreferredStyleSheet() {
  var i, a;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("rel").indexOf("style") != -1
       && a.getAttribute("rel").indexOf("alt") == -1
       && a.getAttribute("title")
       ) return a.getAttribute("title");
  }
  return null;
}

function initAlternate(alternate_base) {
  var alternate_title = null;
  var alternate_cookie = readCookie("USERAGENTSORGstyle");
  var alternate_title = alternate_base ? alternate_base : alternate_cookie ? alternate_cookie : getPreferredStyleSheet();
  setActiveStyleSheet(alternate_title);
}

function terminateAlternate() {
  var title = getActiveStyleSheet();
  createCookie("USERAGENTSORGstyle", title, 365);
}

//init immediato
var alternate_title = null;
var alternate_cookie = readCookie("USERAGENTSORGstyle");
var alternate_base = firstvisit() && screen.width>=1024?'big':null;
var alternate_title = alternate_base ? alternate_base : alternate_cookie ? alternate_cookie : getPreferredStyleSheet();
setActiveStyleSheet(alternate_title);