Non-RegExp Email Validation Script

function validateEmailAddress(emailToValidate) {
	if (emailToValidate == '' || typeof(emailToValidate) == 'undefined') return(false);
	emailToValidate = stringTrim(emailToValidate);
	
	var emailLength = emailToValidate.length;
	var atPos = emailToValidate.indexOf('@');
	var firstDotPos = emailToValidate.indexOf('.');
	var lastDotPos = emailToValidate.lastIndexOf('.');
	
	if (emailLength < 7) return(false);				// minimum email address length ("x@xx.xx")
	if (atPos < 1) return(false);					// traps for no @, or @ as first character
	if (firstDotPos < 1) return(false);				// traps for no ., or . as first character
	if (atPos == emailLength-1) return(false);		// traps for @ as penultimate or last character
	if (lastDotPos >= emailLength-2) return(false);	// traps for too few digits after last . (must be at least 2)
	// traps for @ character next to . character
	if (emailToValidate.charAt(atPos-1) == '.' || emailToValidate.charAt(atPos+1) == '.') return(false);
	return(true);			
}