function isNull(obj) {
	if("" == $.trim(obj)) {
		return true;
	}
	return false;
}

function isMail(obj) {
	var email = $.trim(obj);
	var pattern = /^([a-zA-Z0-9._-])+@([a-zA-Z0-9_-])+(\.[a-zA-Z0-9_-])+/; 
	return pattern.test(email);
}

function isOverOneThousand(num) {
	if(num > 1000) {
		return true;	
	}
	return false;
}