We propose a new mechanism for implementing the electronic shopping cart system (shortly,the shopping cart system)on the World Wide Web system (the Web system).The electronic shopping cart system is one of typical client- server systems,and it includes essential tasks to be implemented in the typical Web based client-server system.The most important task is to maintain context data between successive user sessions. Although several methods,which can be applied to implement the electronic shopping cart on the Web system, have been proposed,any of them can not attain the task of maintaining context data suf .ciently.In this paper we analyze the task and point out the following three difficulties (d1)reliability,(d2)safety,and (d3)session manage- ment.We then propose a new mechanism (called the Context Data Storing (CDS)mechanism)to solve all of (d1),(d2) and (d3).In the proposed CDS mechanism,the context data for the session management is stored in the main memory of the client computer.As a result,the CDS mechanism can achieve both high reliability and high safety as well as the management capability of user sessions. Next,we use component object technology to implement the CDS mechanism.Then,we compared the performance of the electronic shopping cart system using the proposed CDS mechanism with the one using the previous methods. The result showed that our proposed mechanism has solved all dif .culties (d1),(d2)and (d3)and has attained deficient communications between clients and Web servers.