function validCard (numberCard)
{
	String.prototype.startsWith = function (str) {
			return (this.match("^"+str)== str);
	}
	
	val = numberCard.replace(/[^0-9]/g,"");
	
	// mastercard
	if (val.startsWith("5"))
	{
		if (val.length != 16 )
			return false;
		return 'MC'
	} else 
	
	// visa
	if (val.startsWith("4"))
	{
		if (val.length != 16 && val.length != 13)
			return false;
		return 'VI'
	} else
	
	// American Express
	if (val.startsWith("34") || val.startsWith("37"))
	{
		if (val.length != 15)
			return false;
		return 'AE'
	} else
	
	// Discover
	if (val.startsWith("6011"))
	{
		if (val.length != 15 && val.length != 16)
			return false;
		return 'DI'
	}
	
	return false;
	
	
}