var cssList = ['a', 'aa', 'aaa'];
var cssIndex = 0;

function increaseFontSize() {
  var index = cssIndex;
  index++;
    
  if (index < cssList.length) {
    setActiveStyleSheet(cssList[index]);
    cssIndex = index;
  }
}


function decreaseFontSize() {
  var index = cssIndex;
  index--;
    
  if (index >= 0) {
    setActiveStyleSheet(cssList[index]);
    cssIndex = index;
  }
}


function setActiveStyleSheet(title) {
  var i, a, main;
  if ((!title) || (getActiveStyleSheet() === title)) return;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if (isFontSizeStyle(a)) {
      a.disabled = true;
      if(a.getAttribute("title") == title) {
	   a.disabled = false;
      }
    }
  }
}

function isFontSizeStyle(a) {
    if (!a) return false;
    if (a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title")) {

        var re=new RegExp("^a+$", "i"); 
        if (a.getAttribute("title").match(re)) {
 	    return true;
        }
    }
    return false;
}

function getActiveStyleSheet() {
  var i, a;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if (isFontSizeStyle(a) && !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("style");
  var title = cookie ? cookie : getPreferredStyleSheet();
  
  for (var i = 0; i < cssList.length; i++) {
    if (title == cssList[i]) {
        cssIndex = i;
    }
  }
  
  setActiveStyleSheet(title);
}
*/


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




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

for (var i = 0; i < cssList.length; i++) {
  if (title == cssList[i]) {
    cssIndex = i;
  }
}

setActiveStyleSheet(title);