Transclusion is the process of including a portion of one document into the body of a second document. The process is part of a larger method that is known as substitution templates. Transclusion is normally managed with the use of HTML and hypertexting.
The origins of the term transclusion are traced back to the early 1980s. First utilized as terminology within the context of computer science by Ted Nelson, the basic idea was that there was no need for the same data to be stored in more than one place. By making use of linking, the data could be included in two different documents without having to actually copy the information. Nelson is also credited with coining the terms hypertext and hypermedia along with transclusion.
Currently, the scope of usage of transclusion is impacted by the environment in which the usage occurs. For example, the type of browser used may affect how the process will work. Current incarnations of Internet Explorer are sometimes thought to provide a less hospitable environment for the use of transclusions, as the browser can make including portions of a document a little more complicated. Mozilla Firefox is an example of a browser that makes the transclusion of both images and text very easy.
In order to compensate for the differences in browsers, a process that is known as server-side transclusion is sometimes employed. Essentially, this form of transclusion involves caching the data that is transcluded on the server proper. Various applications and documents can access the data directly from the server, rather than creating a link from one document to another. This effectively makes it possible to include the data in several different documents without having to send out the data every time the page is called up.
As the use of the Internet continues to become commonplace in more environments, transclusion continues to be an important component in assembling pages in an efficient manner. To respond to this reality, new versions of browsers are configured to allow for the easy process of transclusion.