var doc = window.document;

function showButton(elem, show) {
	doc.getElementById(elem).style.visibility = show ? 'visible' : 'hidden';
}
function fontsizeup() {
  active = getActiveStyleSheet();
  switch (active) {
    case 'smallest' : 
      setActiveStyleSheet('smaller');
      break;
    case 'smaller' : 
      setActiveStyleSheet('stylesALL');
      break;
    case null : 
      setActiveStyleSheet('larger');
      break;
    case 'larger' : 
      setActiveStyleSheet('largest');
	  showButton('fontlarge', false);
      break;
    case 'largest' :
      break;
    default :
      setActiveStyleSheet('stylesALL');
      break;
  }
  active = getActiveStyleSheet();
  if (active != 'largest') showButton('fontlarge', true);
  if (active != 'smallest') showButton('fontsmall', true);
}

function fontsizedown() {
  active = getActiveStyleSheet();
  switch (active) {
    case 'largest' : 
      setActiveStyleSheet('larger');
      break;
    case 'larger' : 
      setActiveStyleSheet('stylesALL');
      break;
    case null: 
      setActiveStyleSheet('smaller');
      break;
    case 'smaller' : 
      setActiveStyleSheet('smallest');
	  showButton('fontsmall', false);
      break;
    case 'smallest' : 
       break;
    default :
      setActiveStyleSheet('stylesALL');
      break;
  }
  active = getActiveStyleSheet();
  if (active != 'largest') showButton('fontlarge', true);
  if (active != 'smallest') showButton('fontsmall', true);
}

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;
//  return ('smallest');
}

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("style");
  var title = cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);

  if (title != 'largest') showButton('fontlarge', true);
  if (title != 'smallest') showButton('fontsmall', true);
}

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

var cookie = readCookie("style");
var title = cookie ? cookie : getPreferredStyleSheet();
//setActiveStyleSheet(title);
if (title == 'null') {
  title = getPreferredStyleSheet();
}

setActiveStyleSheet(title);