// $Id$

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;
}

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 min=80;
var max=120;
function increaseFontSize() {
   var p = document.getElementById('container');  
    p.style.fontSize = "1.25em"; 
}
function decreaseFontSize() {
   var p = document.getElementById('container');  
    p.style.fontSize = "0.75em"; 
}
function standardFontSize() {
	var p = document.getElementById('container');
    p.style.fontSize = "1em"; 
}

function disable_stylesheets(){
	for ( i=0; i<document.styleSheets.length; i++) {
		void(document.styleSheets.item(i).disabled=true);
	}
}

function enable_stylesheets(){
	for ( i=0; i<document.styleSheets.length; i++) {
		if(document.styleSheets.item(i).title != "lowgraph"){
			void(document.styleSheets.item(i).disabled=false);
		}
	}
}

function changeActive(src,targ){
	var nav = document.getElementById("ternav");
	var childnav = nav.childNodes;
	for(i=0;i<childnav.length;i++){
		childnav[i].className = "";
	}
	//alert(childnav.length);
	src.parentNode.className = "active-tab";
	var content = document.getElementById("contentbox");
	var childcont = content.childNodes;
	for(i=0; i<childcont.length; i++){
		if(childcont[i].childNodes.length){
			childcont[i].className = "invisible";
		}
	}
	document.getElementById(targ).className = "visible";
}