function openPopup(aURL, aName, width, height) {
	//calculate position for centered display
	leftPos = (screen.width) ? (screen.width-width)/2 : 0;
    topPos = (screen.height) ? (screen.height-height)/2 : 0;
    settings = 'height='+height+',width='+width+',top='+topPos+',left='+leftPos+',scrollbars=no, resizable=yes, status=no';
    // open a new window if not existant or refresh the content of the old one
	popupWin = window.open(aURL, aName, settings);
	popupWin.location.href = aURL;
	popupWin.focus();
}


function updateImageBar(title){
	var a;
	a = document.getElementById("img");

	if (title == "modern"){ 
		a.innerHTML = "<img src=\"images\/themes\/modern\/img_bar_personal.jpg\" \/> ";
	} else {
		a.innerHTML = "<img src=\"images\/themes\/modern\/img_bar_titel.jpg\" \/> ";
	}
}

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;
    }
  }
 /* updateImageBar(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 : getPreferredStyleSheet();
  setActiveStyleSheet(title);
}

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

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