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;
	  }
    }
  }
  pressButton(title);
}

function unpressButton(which) {
	document.getElementById(which).src = "images/" + which + ".gif";
}

switchButtons = ["default", "medium", "large"];

function pressButton(which) {
	for (i = 0; i < switchButtons.length; i++) {
		if (which == switchButtons[i]) {
			document.getElementById(which).src = "images/" + which + "_p.gif";
		} else {
			document.getElementById(switchButtons[i]).src = "images/" + switchButtons[i] + ".gif";
		}
	}
	if (which == "null") {
		document.getElementById("default").src = "images/default_p.gif";
	}
}

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) {
	defaultpress = new Image();
	defaultpress.src = "images/default_p.gif";
	mediumpress = new Image();
	mediumpress.src = "images/medium_p.gif";
	largepress = new Image();
	largepress.src = "images/large_p.gif";

	if (document.getElementById) {
  		var cookie = readCookie("style");
		var title = cookie ? cookie : getPreferredStyleSheet();
		setActiveStyleSheet(title);
	}
}

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