function isEmpty (tBox)
{
	return (tBox.value.length == 0);
}

function isEmail(email)
{
	var reg1 = /(@.*@)|(\.\.)|(@\.)|(\.@)|(^\.)/; // not valid
	var reg2 = /^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,3}|[0-9]{1,3})(\]?)$/; // valid
	
	if (reg1.test(email) || reg2.test(email)) { 
		return (true);
	}
}

function showHide(bloco)
{
	var el = document.getElementById(bloco);

	if (el.style.display == 'block' || el.style.display == '')
	{
		el.style.display = 'none';
	}
	else
	{
		el.style.display = 'block';
	}

	return;
}

function validateNota(form)
{
	var nota = form.nota.value; 
	if ( nota > 10 || nota < 1)
	{
		alert('Sua nota deve ser entre 1 e 10');
		return (false);
	}
	return (true);
}