// tnhistoryforkids.org

students = new Image();
students.src = "/images/students_on.gif";

parents = new Image();
parents.src = "/images/parents_on.gif";

teachers = new Image();
teachers.src = "/images/teachers_on.gif";

function switchOn(_image) {
	var navImage = document.getElementById(_image);
	navImage.src = '/images/' + _image + '_on.gif';
}

function switchOff(_image) {
	var navImage = document.getElementById(_image);
	navImage.src = '/images/' + _image + '.gif';
}

function showImage () {
	if (imageTotal) {
		imageNo = Math.floor(Math.random() * imageTotal) + 1;
		var image = document.getElementById('image_' + imageNo);
		image.style.display = 'block';
		setInterval('rotateImage(' + imageNo + ')', 20000);
	}
}

function rotateImage (_initImageNo) {
	if (imageNo < 1) {
		imageNo = _initImageNo;
	}
	var oldImage = document.getElementById('image_' + imageNo);
	imageNo++;
	if (imageNo > imageTotal) { imageNo = 1; }
	var newImage = document.getElementById('image_' + imageNo);
	oldImage.style.display = 'none';
	newImage.style.display = 'block';
}

function showSidebarImage () {
	if (sidebarImageTotal) {
		sidebarImageNo = Math.floor(Math.random() * sidebarImageTotal) + 1;
		if (sidebarImageNo == imageNo) {
			sidebarImageNo++;
			if (sidebarImageNo > sidebarImageTotal) { sidebarImageNo = 1; }
		}
		var image = document.getElementById('sidebar_image_' + sidebarImageNo);
		image.style.display = 'block';
		setInterval('rotateSidebarImage(' + sidebarImageNo + ')', 20000);
	}
}

function rotateSidebarImage (_initImageNo) {
	if (sidebarImageNo < 1) {
		sidebarImageNo = _initSidebarImageNo;
	}
	var oldImage = document.getElementById('sidebar_image_' + sidebarImageNo);
	sidebarImageNo++;
	if (sidebarImageNo > sidebarImageTotal) { sidebarImageNo = 1; }
	var newImage = document.getElementById('sidebar_image_' + sidebarImageNo);
	oldImage.style.display = 'none';
	newImage.style.display = 'block';
}