function ChWinter() {
	document.getElementById('Winter').style.background="#4E82B1";
	document.getElementById('Spring').style.background="none";
	document.getElementById('Summer').style.background="none";
	document.getElementById('Autumn').style.background="none";	
}
function ChSpring() {
	document.getElementById('Spring').style.background="#5D9066";
	document.getElementById('Winter').style.background="none";
	document.getElementById('Summer').style.background="none";
	document.getElementById('Autumn').style.background="none";	
}
function ChSummer() {
	document.getElementById('Summer').style.background="#3CA73F";
	document.getElementById('Winter').style.background="none";
	document.getElementById('Spring').style.background="none";	
	document.getElementById('Autumn').style.background="none";
}
function ChAutumn() {
	document.getElementById('Autumn').style.background="#A7A13C";
	document.getElementById('Winter').style.background="none";
	document.getElementById('Spring').style.background="none";
	document.getElementById('Summer').style.background="none";	
}
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;
}
window.onload = function(e) {
var now = new Date();
var month = now.getMonth() + 1;
ChWinter();
if (month > 2 && month < 6) ChSpring();
if (month > 5 && month < 9) ChSummer();
if (month > 8 && month < 12) ChAutumn();
}