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;
}


function changeStyleSheetRule ( selector, suchEigenschaft, neuerWert, setCookie ) {

  var msie	= false;
  var dom2	= false;
  var domRegeln	= null;
  var cssRegel	= "";

  if ( setCookie && selector == "*" ) {
	createCookie(suchEigenschaft, neuerWert, 365);
  }

  for ( var cssNr=0; cssNr < document.styleSheets.length; cssNr++ ) {
  	aktSheet	= document.styleSheets[cssNr];
  	if ( aktSheet ) {
    		if ( aktSheet.rules ) {	// MISE
			domRegeln = aktSheet.rules;
			msie	  = true;
    		}
    		else if ( aktSheet.cssRules ) { // DOM 2
			domRegeln = aktSheet.cssRules;
			dom2	  = true;
    		}

    		for ( i=0; i < domRegeln.length; i++ ) {
			cssRegel = domRegeln[i];

			if ( cssRegel ) {
	
				if ( cssRegel.selectorText == selector || (selector == "*" && cssRegel.selectorText == "") ) {
					var neueEigenschaft = "";
					var found = false;
					if ( dom2 ) {
						for ( var z=0; z<cssRegel.style.length; z++ ) {
							var orgEigenschaft = cssRegel.style[z];
							var eigenschaft = orgEigenschaft.replace(/-/g, "").toLowerCase();
							var wert = cssRegel.style.getPropertyValue(cssRegel.style[z]);
							if ( eigenschaft == suchEigenschaft.toLowerCase() ) {
								wert = neuerWert;
								found = true;
							}
							if ( wert != "" ) neueEigenschaft += orgEigenschaft + ": " + wert + "; ";
						}
						if ( !found ) neueEigenschaft += suchEigenschaft + ": " + neuerWert + "; ";
						if ( neueEigenschaft != "" ) {
							neueEigenschaft = selector + " { " + neueEigenschaft + " }";
							newIndex = aktSheet.insertRule( neueEigenschaft, aktSheet.cssRules.length );
							aktSheet.deleteRule ( i );	// alte Regel loeschen
							break;
						}
					}
					else if ( msie ) {
						for ( var eigenschaft in cssRegel.style ) {
							var orgEigenschaft = eigenschaft;
							var eigenschaft = orgEigenschaft.replace(/-/g, "").toLowerCase();
							var wert = "";
							wert = cssRegel.style[eigenschaft];
							if ( eigenschaft == suchEigenschaft.toLowerCase() ) {
								wert = neuerWert;
								found = true;
							}
							if ( wert && wert != "" ) neueEigenschaft += orgEigenschaft + ": " + wert + "; ";
						}
						if ( !found ) neueEigenschaft += suchEigenschaft + ": " + neuerWert + "; ";
						if ( neueEigenschaft != "" ) {
							aktSheet.addRule ( selector, neueEigenschaft );
							//aktSheet.removeRule(i);	// alte Regel loeschen (MSIE verweigert die Erlaubnis)
							i = domRegeln.length;
						}
					}
				
				}

			}
    		}
  	}
  }

}


window.onload = function(e) {
  var cookie = readCookie("stylesheet");
  var title = cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);

  var fontsize = readCookie("font");
  changeStyleSheetRule ( "*", "font", fontsize, false );
}

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

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

var fontsize = readCookie("font");
changeStyleSheetRule ( "*", "font", fontsize, false );