function toggleNav(chapter,count){
	var name = chapter + '_1';
	
	if (document.getElementById(name).style.display == 'block')
		var toggle_switch = 'none';
	else
		var toggle_switch = 'block';
	
	for (var i = 0; i < count; i++) {
		name = chapter + '_' + i;
		document.getElementById(name).style.display = toggle_switch;
	}
}

function toggleOn(chapter,count){
	var name = chapter + '_1';

	for (var i = 0; i < count; i++) {
		name = chapter + '_' + i;
		document.getElementById(name).style.display = 'block';
	}
}

function toggleOff(chapter,count){
	var name = chapter + '_1';

	for (var i = 0; i < count; i++) {
		name = chapter + '_' + i;
		document.getElementById(name).style.display = 'none';
	}
}