var state = 'none'; 

function showhide(layer_ref)
{ 
	if (state == 'block')
	{ 
		state = 'none'; 
	} 
	else
	{ 
		state = 'block'; 
	} 
	if (document.all) { //IS IE 4 or 5 (or 6 beta) 
		eval( 'document.all.' + layer_ref + '.style.display = state'); 
	} 
	if (document.layers) { //IS NETSCAPE 4 or below 
		document.layers[layer_ref].display = state; 
	} 
	if (document.getElementById &&!document.all) { 
		hza = document.getElementById(layer_ref); 
		hza.style.display = state; 
	} 
}

function isEmail (tBox)
{
	var bln = false;
	var s = String(tBox.value);
	var l = parseInt(s.length);
	var i, j;
	for (i = 0; i < l ; i++) {
		if (s.charAt(i) == '@' && i > 0) {
			for (j = i; j < l ; j++) {
				if (s.charAt(j) == '.' && (l > j+2) && j!= i+1 && j!= i+2) {
					bln = true;
				}
			}
		}
	}
	if (!bln) alert('Favor entrar com e-mail válido\n');
	return (bln);
}

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


function isNumeric(sText)
{
   var validChars = "0123456789.";
   var isNumber=true;
   var char;

   for (i = 0; i < sText.length && isNumber; i++) 
   { 
      char = sText.charAt(i); 
      if (validChars.indexOf(char) == -1) 
      {
         isNumber = false;
      }
   }
   return isNumber;
}