// ----------------------------------------------
// StyleSwitcher functions written by Paul Sowden
// http://www.idontsmoke.co.uk/ss/
// - - - - - - - - - - - - - - - - - - - - - - -
// For the details, visit ALA:
// http://www.alistapart.com/stories/alternate/
//
// nifty StyleSwitcher scripts modified by Aaron Jones 10/10/2002
// ----------------------------------------------

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 = !(a.getAttribute("title") == title);
    }
  }
}

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("style");
  var title = cookie && cookie!="null" ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);
  substituteLinks();
}

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

// Funciones para incluir tracking de enlaces
function getElementsByClass(searchClass,tag) {
  var classElements = new Array();
  if (tag==null)
    tag = '*';
  var els = document.getElementsByTagName(tag);
  var elsLen = els.length;
  var pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)");
  for (i=0, j=0; i<elsLen; i++) {
    if (pattern.test(els[i].className)) {
       classElements[j] = els[i];
       j++;
    }
  }
  return classElements;
}

function substituteLinks() {
  var els = getElementsByClass("enlace", "a");
  var elsLen = els.length;
  for (i=0; i<elsLen; i++)
    els[i].href = "/visitar.php?url="+els[i].href;
}