var page = 1;

function nextThumbs(nextButton, prevButton) {

	if (document.getElementById('T-' + (page + 1))) {

		var thumbs;
		thumbs = document.getElementById('T-' + page);
		thumbs.style.display = 'none';

		page++;

		thumbs = document.getElementById('T-' + page);
		thumbs.style.display = 'block';
			
		document.getElementById(prevButton).style.display = 'block';

		if (!document.getElementById('T-' + (page + 1))) {
			
			document.getElementById(nextButton).style.display = 'none';
		}

	} else {

		document.getElementById(nextButton).style.display = 'none';

	}

}

function prevThumbs(prevButton, nextButton) {

	if (document.getElementById('T-' + (page - 1))) {

		var thumbs;
		thumbs = document.getElementById('T-' + page);
		thumbs.style.display = 'none';

		page--;

		thumbs = document.getElementById('T-' + page);
		thumbs.style.display = 'block';

		document.getElementById(nextButton).style.display = 'block';

		if (!document.getElementById('T-' + (page - 1))) {
			
			document.getElementById(prevButton).style.display = 'none';
		}

	} else {

		document.getElementById(prevButton).style.display = 'none';

	}

}