function validate_email (addr) {
	var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(addr)) return true;
	else return false;
}
function check_num (pseudo_num) {
	var allowed_chars = "0123456789+()- ";
	var pseudo_num_ok = true;
	var valid_output  = "";

	for (i = 0; i < pseudo_num.length; i++) {
		ch = pseudo_num.charAt(i);
	
		for (j = 0;  j < allowed_chars.length;  j++)
			if (ch == allowed_chars.charAt(j))
				break;
	
		if (j == allowed_chars.length) {
			pseudo_num_ok = false;
			break;
		}
	}
	if (!pseudo_num_ok) {
		return false
	} else {
		return true;
	}
}