Client versus Server Side Functionality in E-Commerce, Storefront Applications

    January 19, 2004

E-Commerce, E-Business, Internet Shopping, On-line Storefronts, Digital Storefronts, Electronic Shopping, Internet Commerce, Web Commerce, B2B, B2C, etc. are all terms used by marketing to grab a “mind share”. They all refer to buying and selling over the Internet.

Client-Server, client side functionality, server side storefronts, thin client, server enabled, client enabled are terms that, if you’re a busy Internet shopper, are important to you. They refer to the way your Internet shopping session functions.

A server is a terminal device that delivers information in response to a request. Your telephone answering machine is a server terminal. The telephone you use to make a call is a client terminal. When you make a call and get an answering machine, the message from the machine is passed on to you via the client machine, your telephone.

What do telephone answering machines have to do with Internet Commerce? Well, like that telephone system, all Internet shopping involves at least two terminals: the server machine which is sometimes called the host computer, and the client machine which is your computer.

In e-commerce, the essential server or host function is to store, and make available to a client machine, all of the information that is unique to a store on the Internet. This unique information will include:

  • product data and descriptions
  • data controlling the look and feel of the storefront itself
  • feedback pertaining to the actual purchases by the customer

Your computer, the client machine, will run a web browser application which allows you to view the unique store information as hypertext pages. These pages have the capacity to provide rich presentations of audio, video, images, and text.

In addition to the unique functions in e-commerce, there are numerous generic functions that must be performed to complete the on-line shopping experience. Either the server machine or your computer can perform them. Some of these functions are:

  • saving product selections to temporary memory
  • computing taxes
  • computing shipping costs
  • totaling your order
  • getting gift wrap instructions
  • forms checking
  • getting shipping instructions
  • remembering who you are and what you bought last time
  • generating a purchase order
  • sending you an e-mail confirmation of the order
  • credit card verification (This is not card authorization which is strictly a server side function.)

To a shopper or a merchant, it can make a big difference in time and efficiency, just where these generic functions are performed. If you’re like most of us, you hate standing in line at the check out counter, hate price checks, hate waiting while a clerk tries to find an item, hate….well anything that delays your trip to the beach. To that end, you need to know what kind of software the merchant is using.

E-Commerce, storefront software can be either client side or server side functional. Simply put, the type of software will determine whether generic functions are performed on the server computer or your computer.

To demonstrate how this affects you, take a look at a real world paradigm which probably best emulates a virtual world shopping experience. It’s the type of store where you view items on a display floor and write down the item number on a pad. You keep doing this for each item you want until you’re ready to check out. At which time you go to a central location where a clerk totals the price and tax for everything you’ve selected; you make payment arrangements, and pick up your purchases.
Now do this in the virtual world using e-commerce software that has to perform all of the generic functions on the server machine. Select an item from the display floor. Write down the item number. Take the slip of paper to the check out counter and ask the clerk to compute your taxes and shipping costs on that item, and hold the slip for you while you look around the store some more. Select another item, take a new slip paper to checkout, ask the clerk….you get the idea. Server side functionality means that each time you make a selection, you must repeatedly go back to the clerk (server) to hold that selection for you. It also means that if you want to see what your total purchases, shipping costs and taxes are, at any time, you must go back and ask the clerk to make the computation.

However, the clerk, the server computer, is very fast, so why is this a problem? The problem is that each item you select is about a mile away from the checkout location and the clerk is very busy. You have to walk this mile each time you make a selection. And you have to stand in line waiting while the clerk serves other customers.

How long can that take? Consider that that mile represents the time it takes to request a page and get a response over the Internet…you can judge this for yourself. The clerk is the server machine. If it’s just you that needs the clerk….no problem. If one hundred shoppers show up at the clerk’s location at one time….expect to wait. If you’re a customer, you may just go home. If you’re a merchant, you’re in big trouble. You may be losing customers.

The irony of this server side scenario is that while you wait for each transaction from the server, your own computer sits idle. To address this wasted capability, client side storefront software was developed.

A client side storefront runs in the web browser, on your machine. It performs all of the generic on-line shopping functions on the fly. That is: it stores all of your product selections, cost information, and shipping instructions in the browser session; it can save information about you and your purchases on your computer; it totals the order and displays taxes and shipping costs almost instantly; and, it presents a complete purchase order for your review, without delay and without ever having to make another request of the server. In fact the only time client side storefronts have to connect back to the host server machine is to request new information unique to the store or send a summary of the completed shopping session.

Client side e-commerce software is generally written in hypertext markup language (HTML) using JavaScript scripts to provide the various generic e-commerce functions. Both of these languages are ubiquitous and run in the client machine’s web browser without relying on any special server side functions. This means the merchant owns and operates their own store independent of the host computer and any special server e-commerce software. It means that the storefront is portable and can be hosted just about anywhere, from any Internet Service Provider.

If you’re a shopper, you want speed. If you’re a merchant, you want happy shoppers. Client side, e-commerce, storefront software delivers both.

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Mel Davey is the creator of ImagineNation (, a full service E-Commerce Application Service Provider, offering Storefronts, Order Management Utilities, and 3rd party credit card processing.