/************************************
	E-mail-validation script v1.3

	Subsero A/S (subsero.dk)
*************************************

v1.3 (Torben Rohde, 13/12-2007)
-------------------------------
Added an overload with a nicer name (isEmailValid). This version is fully compatible with 1.2


v1.2 (Torben Rohde, 28/7-2006)
-------------------------------
Added 4 letter TLD as valid domain name (e.g. .info)

v1.1 (Torben Rohde, 9/5-2006)
--------------------------------
Fixed bug: Address in the form myaddress@.dk was accepted as valid
The function was almost completely rewritten

v1.0 (Torben Rohde, 25/10-2001)
--------------------------------
Initial version
*/

function isEmailValid(email)
{
	return validateEmail(email)
}

//Validate the e-mail address (returns true if all ok, else possibly the character that is not allowed or simply false)
function validateEmail(email) 
{
	//invalidChars = "	 /:,;£$€{[]}|´!\"#¤%&()=?`½§\\*+'<>æøå^";
	invalidChars = "\t \x2F\x3A\x2C\x3B\xA3\x24\x20AC\x7B\x5B\x5D\x7D\x7C\xB4\x21\x5C\x22\x23\xA4\x25\x26\x28\x29\x3D\x3F\x60\xBD\xA7\x5C\x5C\x2A\x2B\x27\x3C\x3E\xE6\xF8\xE5\x5E";

	//Any invalid chars?
		for (i = 0; i < invalidChars.length; i++) {
			checkChar = invalidChars.charAt(i)
			if (email.indexOf(checkChar, 0) > - 1) {
				return false;
			}
		}

	//Check the occurence of the @ char
		var emailParts = email.split('@');
		if (emailParts.length == 1) {
			//string did not contain @
			return false;
		}
		else if (emailParts.length > 2) {
			//string did not contain more than one @
			return false;
		}
		else if (emailParts.length != 2) {
			//unknown error, should not occur
			return false;
		}

	var emailAccountName = emailParts[0];
	var emailDomain = emailParts[1];

	//Correct account name?
		if (emailAccountName.length == 0) {
			//no account name
			return false;
		}
		var emailAccountNameFirstChar = emailAccountName.charAt(0);
		var emailAccountNameLastChar = emailAccountName.charAt(emailAccountName.length-1);

		if (emailAccountNameFirstChar == ".") {
			//account name must not start with .
			return false;
		}
		if (emailAccountNameLastChar == ".") {
			//account name must not end with .
			return false;
		}

	//Correct domain
		if (emailDomain.length == 0) {
			//no account name
			return false;
		}
		//domain must end in two or three letters after .
			if (emailDomain.indexOf(".") == -1) {
				//no . in domain
				return false;
			}
			var topLevelDomainName = emailDomain.substring(emailDomain.lastIndexOf(".")+1, emailDomain.length);
			if (topLevelDomainName.length != 2 && topLevelDomainName.length != 3 && topLevelDomainName.length != 4) {
				//invalid top-level-domain (must be e.g. dk or com)
				return false;
			}
			//check that there are not two dots next to each other
				if (emailDomain.indexOf("..") != -1) {
					//invalid domain, contains double .
					return false;
				}

			var subdomain = emailDomain.substring(0, emailDomain.lastIndexOf("."));
			if (subdomain.length == 0) {
				//no subdomain specified (e.g. myaccount@.com)
				return false;
			}
		var emailDomainFirstChar = emailDomain.charAt(0);
		if (emailDomainFirstChar == ".") {
			//account name must not start with .
			return false;
		}
	//All ok
	return true;
}