function updatePreview () {
	var chan = document.getElementById ('chan').value;
	var theme = document.getElementById ('theme').value;
	var digits = document.getElementById ('digits').value;
	var domain = document.getElementById ('domain').value;
	var url = 'http://tools.' + domain + '/counter/' + chan + '/' + theme + '/' + digits + '/';

	document.getElementById ('preview').src = url;
	document.getElementById ('url').innerHTML = url;
	document.getElementById ('tag').innerHTML = '<img src="' + url + '">';
}

function preview (color, box) {
	if (obj = document.getElementById ('p' + box)) {
		var check = /#[0-9A-F]{6}/i
		if (check.test (color))
			obj.style.backgroundColor = color;
	}
}