function showRating(rating) {
	var ratingStars = document.getElementById('ratingStars');
	yPos = (rating) * 23;
	ratingStars.style.backgroundPosition = "0px -" + yPos + "px";
}

function resetRating() {
	var ratingStars = document.getElementById('ratingStars');
	var curRating = document.getElementById('rating').value;
	yPos = (curRating) * 23;
	ratingStars.style.backgroundPosition = "0px -" + yPos + "px";
}

function setRating(rating) {
	var ratingStars = document.getElementById('ratingStars');
	document.getElementById('rating').value = rating;
	return false;
}

// JavaScript Document
function checkCommentForm() {
	var myForm = document.forms.commentForm;
	
	if (!myForm.name.value) {
		alert('Por favor, ingrese su nombre.');
		myForm.name.focus();
		return false;
	}

	if (!myForm.email.value) {
		alert( 'Por favor, ingrese su email.' );
		myForm.email.focus();
		return false;
	}
	else {
		if (!validEmail( myForm.email.value )) {
			alert( 'El Email ingresado no es válido. Por favor, inténtelo de nuevo.' );
			myForm.email.focus();
			return false;
		}
	}

	if (myForm.rating.value == 0) {
		alert('Por favor, califique este producto.');
		return false;
	}

	if (!myForm.comment.value) {
		alert('Por favor, ingrese su comentario.');
		myForm.comment.focus();
		return false;
	}
	
	return true;
}

function validEmail( email ) {
	mailReg = /^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/;
	if (email.match(mailReg) )
		return true;
	else
		return false;
}