// $Id: js.js,v 1.18 2006/01/09 14:47:09 unrz109 Exp $
// This script based on Paul Snowden's work described on A List Apart
//  <http://www.alistapart.com/stories/alternate/>
// Certain modifications (setFontSize and related) by Eric Meyer
//  <http://www.meyerweb.com/eric/>
// Weitere Modifikationen von Wolfgang Wiese
// <http://www.xwolf.de>
// Rewrite von Volker Buzek für GIB Seite
// <http://www.rrze.uni-erlangen.de>

function setActiveStyleSheet(title) {
	var i, a;
	for(i=0; (a = document.getElementsByTagName('link')[i]); i++) {
		if(a.getAttribute('rel').indexOf('style') != -1 && a.getAttribute('title') && a.getAttribute('title') != 'default') {
			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.getAttribute("title") != 'default' &&
  			!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") != 'default' &&
    		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;
}

function eraseCookie(name) {
	createCookie(name,'',-1);
}

window.onload = function(e) {
  var cookie = readCookie('gib-style');
  var title = cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);
}

window.onunload = function(e) {
  var title = getActiveStyleSheet();
  createCookie('gib-style', title, 14);
}

/******************************************/

function printStyleSwitch() {
	document.write("<ul id=\"navispalte\"><li><a href=\"#\" onclick=\"setActiveStyleSheet(\'noleftbox\'); return false;\">Navigation ausblenden<\/a><\/li><\/ul>");
}