The Purpose

This article describes a challenge caused by Ajax. As we know, Ajax updates a Web page asynchronously by communicating with the server. Like any asynchronous communication, it introduced the race condition. It is not easy to resolve because of the stateless nature of the HTTP protocol.

Phenomena

Assume you have an expense claim as follows.

Item	Amount</td
<select> <option></option> <option>Postage</option> <option>Toll</option>