function is_valid_email(email)
{
	var atPos = email.indexOf('@');
	// No '@' or '@" at beginning of email
	if(-1 == atPos || 0 == atPos)
		return false;
	
	// Spaces or tabs
	if(-1 != email.indexOf(' ') || -1 != email.indexOf('\t'))
		return false;
	
	var dotPos = email.indexOf('.', atPos);
	// No dot, or dot directly after '@'
	if(-1 == dotPos || atPos + 1 == dotPos)
		return false;
	
	// Dot is last character
	if(email.length - 1 == dotPos)
		return false;
		
	return true;
}