var myAccordion;

window.onload = function(){
	var myStretch = document.getElementsByClassName('stretch'); //elemento sobre el cual hago click
	var myStretcher = document.getElementsByClassName('stretcher'); //elemento que "hago aparecer" 
	myAccordion = new fx.Accordion(myStretch, myStretcher, {opacity: false});
	
	try{ myAccordion.showThisHideOpen(document.getElementById('alternativas')); }
	catch(e){}
}