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 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;
}

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

function setFontSize(size) {
	var body = document.getElementsByTagName('body')[0];
	var percentuale = "76%"; // default
	if (size == 1) percentuale = "70%";
	if (size == 2) percentuale = "76%";
	if (size == 3) percentuale = "90%";
	if (size == 4) percentuale = "100%";
	if (size == 5) percentuale = "110%";
	body.style.fontSize = percentuale;
	createCookie('aa_font_size', size, 365);
}

function revertStyles(){
	setFontSize(2);
}

function intercetta() {
    for (var i=0; i<document.links.length; i++)
        if ((document.links[i].className=="blank") ) {
            document.links[i].target="_blank";
        }
}

function getById(name){
    if (document.getElementById) return document.getElementById(name);  // Mozilla, Safari, W3C
    else if (document.all) return document.all[name];                   // Internet Explorer
    else if (document.layers) return document.layers[name];             // Netscape 4
    return null;
} 


window.onload = function(e) {

	size = readCookie('aa_font_size');
	setFontSize(size);

  	var cookie = readCookie("aa_style");
  	var title = cookie ? cookie : getPreferredStyleSheet();
  	setActiveStyleSheet(title);
}

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