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This becomes a lot of work very quickly. As you can imagine, with any more than a few pages to update every day, this can become pretty dull. The webmaster also understandably makes mistakes (he's human, after all), and forgets to update or remove critical pages.

Somewhere down the line smart webmasters begin to think to themselves, "Wow, this is a lot of work. It's tedious and complicated, and I seem to be making a lot of mistakes. Computers are really good at doing tedious and complicated tasks, and they don't make very many mistakes. I bet my webserver computer can automatically do a lot of the work I now do manually." At this point, the webmaster is ready to be introduced to web applications .

A web application is a computer program that users invoke by using a web browser to contact a web server via the Internet. Users and browsers are typically unaware of the difference between contacting a web server which fronts for a statically-built website and a web server which fronts for a web application. But unlike a static website, a web application creates its "pages" dynamically . A website that is dynamically-constructed uses an a computer program to provide the dynamism. These kinds of dynamic capplications can be written in any number of computer languages. In a dynamically-constructed website, the webmaster is not required to visit the site "page-by-page" in order to update content or style. Instead, he is able to create a "common look and feel" for the set of pages that make up his website. He is also able to instruct the webserver to generate an HTML page on the fly that includes certain unique bits of content. If our auto-classified-ad webmaster chose to construct a web application to maintain his classifieds system, he could maintain a list of "current" ads separate from the HTML layout (perhaps stored in a database of some kind). He could then instruct his web application to query this database and generate a particular chunk of HTML that represented an ad or an index of ads when a user visited a page in his website.

Web applications are everywhere. Common examples of web applications are those that let you search the web, like Google ; collaborate on projects, like SourceForge ; buy items at an auction like eBay ; communicate with other people over e-mail, like Hotmail ; or view the latest news ala CNN.com .

A framework which allows people to construct a web application is often called a web application server , or sometimes just an application server . Zope is a web application server, as are competing products like BEA WebLogic , Macromedia Cold Fusion and (to some extent) Vignette Story Server . A web application server typically allows a developer to create a web application using some common computer programming language. But it also provides services beyond the basic capabilities of the language such as templating, a common security model, data persistence, sessions, and other features that people find useful when constructing a typical web application.