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Maintaining Context in a Web TransactionLocate this document in the navigation structure

Use

The Internet provides a network of HTML pages connected by hypertext links, but these pages do not share a common context - every page is fetched from the Web server individually.

When you develop applications that use HTML pages, the pages need to be logically connected by an application context. However, Web servers do not provide a means for sharing context.

Context and Transaction Flow

The Internet Transaction Server (ITS) solves this problem by associating pages with a connection to the SAP system. Even if pages are retrieved individually from the Web server, the ITS still knows that a certain page belongs to the transaction currently running in the SAP system.

Another benefit of a permanent connection to the SAP system is that the transaction can keep its roll area. This improves performance and provides the ability to maintain an application context. When pages are generated, they are generated in the context of the current contents of the transaction's roll area. As the user progresses through the application, the roll area may change, and the generated HTML pages reflect that change.

Context and Web Browser Navigation

Progressing screen by screen through a transaction is not a problem, but what happens if the user navigates between HTML pages using the Web browser's Back button or History function? In the latter case, the user can even go back multiple steps. Progressing through a transaction changes the roll area, but an arbitrary step backward cannot recover the state of the roll area. As a result, it may be difficult or even impossible to regenerate the HTML page.

To solve this problem, keep in mind that even though the ITS keeps the connection to the SAP system alive, pages are still retrieved from the Web server individually, depending on user input. Only when all parameters required to generate a page are part of a request can the page be fully restored.

If too many parameters are required, or it is not possible to determine the set of parameters needed to generate the page, SAP recommends you Disable Synchronization.