// activeCSS: Set the active stylesheet
function activeCSS(title) {
  var i, oneLink;
  for (i = 0; (oneLink = document.getElementsByTagName("link")[i]); i++) {
    if (oneLink.getAttribute("title") && findWord("stylesheet", oneLink.getAttribute("rel"))) {
      oneLink.disabled = true;
      if (oneLink.getAttribute("title") == title) {
        oneLink.disabled = false;
      }
    }
  }
}

// findWord: Used to find a full word (needle) in a string (haystack)
function findWord(needle, haystack) {
  return haystack.match(needle + "\\b");
}


// prototype StyleManger {
  function StyleManager() {
    this.varsion = '1.0';
  }  
  
  StyleManager.prototype.changeStylesheet = function(url) {
    this.removeStylesheet();
    this.addStylesheet(url);
  }
  
  StyleManager.prototype.addStylesheet = function(url) {
    var head = document.getElementsByTagName('head')[0];
    var link = document.createElement('link');
    link.id = 'myStylesheet'
    link.rel = 'stylesheet';
    link.type = 'text/css';
    link.href = url;
    head.appendChild(link);
  }
  
  StyleManager.prototype.removeStylesheet = function() {
    var head = document.getElementsByTagName('head')[0];
    var link = document.getElementById('myStylesheet');
    if(link) {
      head.removeChild(link);
    }
  }
// }
  
  var StyleManager = new StyleManager();