function btn_load(){

    $$('.btnS').each(function(s, index) { s.observe('mouseover', respondToOverS); });
	$$('.btnS').each(function(s, index) { s.observe('mouseout', respondToOutS); });
	$$('.btnM').each(function(s, index) { s.observe('mouseover', respondToOverS); });
	$$('.btnM').each(function(s, index) { s.observe('mouseout', respondToOutS); });
	$$('.btnL').each(function(s, index) { s.observe('mouseover', respondToOverS); });
	$$('.btnL').each(function(s, index) { s.observe('mouseout', respondToOutS); });
	$$('.btnX').each(function(s, index) { s.observe('mouseover', respondToOverS); });
	$$('.btnX').each(function(s, index) { s.observe('mouseout', respondToOutS); });
	$$('.btnXL').each(function(s, index) { s.observe('mouseover', respondToOverS); });
	$$('.btnXL').each(function(s, index) { s.observe('mouseout', respondToOutS); });
	$$('.btnPart').each(function(s, index) { s.observe('mouseover', respondToOverP); });
	$$('.btnPart').each(function(s, index) { s.observe('mouseout', respondToOutP); });
}

function respondToOverS(event) {
  var element = Event.element(event);
  element.setStyle({background: 'url(images/btn-hover.gif) repeat-x 0 0'});
}

function respondToOutS(event) {
  var element = Event.element(event);
  element.setStyle({background: '#4c7ba9'});
}

function respondToOverP(event) {
  var element = Event.element(event);
  element.setStyle({background: 'url(images/btn-participate.gif) no-repeat left top'});
}

function respondToOutP(event) {
  var element = Event.element(event);
  element.setStyle({background: 'url(images/btn-participate-h.gif) no-repeat left top'});
  //element.setStyle({background: '#4c7ba9'});
}