function changeSymbol(id) {
	var obj = document.getElementById(id);

	alert(obj.innerHTML);
	if (obj.innerHTML == '►') {
		alert('aqui');
		obj.innerHTML = '▼';
	} else if(obj.innerHTML == '▼') {
		alert('aqui2');
		obj.innerHTML = '►';
	}
	//obj.innerHTML = '▼';
	return false;
}