// This CSS style switcher courtesy of Paul Snowden
// (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.getAttribute("title") == '' && title=='standard')) a.disabled = false;
    }
  }
}
function setActiveStyleSheetWindow(aWindow, title) {
  var newtitle = title != "null" ? title : "standard";
  var ss = document.createElement("link");
  ss.type = "text/css";
  ss.rel = "stylesheet";
  ss.href = "/ams/site_media/static/conference/css/" + newtitle + ".css";

  var iframe;

  if(document.frames)
	iframe = document.frames[aWindow];
  else {
	iframe = window.frames[aWindow];
  }
if (iframe) {
  if(document.all)
	iframe.document.createStyleSheet(ss.href);
  else {
	iframe.document.getElementsByTagName("head")[0].appendChild(ss);
  }
}
}
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 createCookie(name,value,days) {
  if (days) {
    var date = new Date();
    date.setTime(date.getTime()+(days*24*60*60*1000));
    var expires = "; expires="+date.toGMTString();
  }
  else expires = "";
  document.cookie = name+"="+value+expires+"; path=/";
}

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

window.onload = function(e) {
  var cookie = readCookie("ams-fontsize");
  var title = cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);
  setActiveStyleSheetWindow("kurs", title);
}

window.onunload = function(e) {
  var title = getActiveStyleSheet();
  createCookie("ams-fontsize", title, 365);
}

var cookie = readCookie("ams-fontsize");
var title = cookie ? cookie : getPreferredStyleSheet();
setActiveStyleSheet(title);
//setActiveStyleSheetWindow("kurs", title);