function emailCheck (emailStr) {	
	/* The following variable tells the rest of the function whether or not
	to verify that the address ends in a two-letter country or well-known
	TLD.  1 means check it, 0 means don't. */
	
	var checkTLD=1;
	
	/* The following is the list of known TLDs that an e-mail address must end with. */
	
	var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
	
	/* The following pattern is used to check if the entered e-mail address
	fits the user@domain format.  It also is used to separate the username
	from the domain. */
	
	var emailPat=/^(.+)@(.+)$/;
	
	/* The following string represents the pattern for matching all special
	characters.  We don't want to allow special characters in the address. 
	These characters include ( ) < > @ , ; : \ " . [ ] */
	
	var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
	
	/* The following string represents the range of characters allowed in a 
	username or domainname.  It really states which chars aren't allowed.*/
	
	var validChars="\[^\\s" + specialChars + "\]";
	
	/* The following pattern applies if the "user" is a quoted string (in
	which case, there are no rules about which characters are allowed
	and which aren't; anything goes).  E.g. "jiminy cricket"@disney.com
	is a legal e-mail address. */
	
	var quotedUser="(\"[^\"]*\")";
	
	/* The following pattern applies for domains that are IP addresses,
	rather than symbolic names.  E.g. joe@[123.124.233.4] is a legal
	e-mail address. NOTE: The square brackets are required. */
	
	var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
	
	/* The following string represents an atom (basically a series of non-special characters.) */
	
	var atom=validChars + '+';
	
	/* The following string represents one word in the typical username.
	For example, in john.doe@somewhere.com, john and doe are words.
	Basically, a word is either an atom or quoted string. */
	
	var word="(" + atom + "|" + quotedUser + ")";
	
	// The following pattern describes the structure of the user
	
	var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
	
	/* The following pattern describes the structure of a normal symbolic
	domain, as opposed to ipDomainPat, shown above. */
	
	var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
	
	/* Finally, let's start trying to figure out if the supplied address is valid. */
	
	/* Begin with the coarse pattern to simply break up user@domain into
	different pieces that are easy to analyze. */
	
	var matchArray=emailStr.match(emailPat);
	
	if (matchArray==null) {
	
	/* Too many/few @'s or something; basically, this address doesn't
	even fit the general mould of a valid e-mail address. */	
		//alert("La dirección de email parece incorrecta (comprueba @ y .)");
		return false;
	}else{
		return true;
	}
}

function getYear(d) { 
  return (d < 1000) ? d + 1900 : d;
  }

//Valida una fecha, viene acompañada de la funcion getYear
function isDate (day, month, year) {
  // month argument must be in the range 1 - 12
  month = month - 1;  // javascript month range : 0- 11
  var tempDate = new Date(year,month,day);
  if ( (getYear(tempDate.getYear()) == year) &&
     (month == tempDate.getMonth()) &&
     (day == tempDate.getDate()) )
      return true;
  else
     return false
  }