About TEI Boilerplate
TEI Boilerplate is a lightweight solution for publishing styled TEI (Text Encoding Initiative) P5 content directly in modern browsers. With TEI Boilerplate, TEI XML files can be served directly to the web without server-side processing or translation to HTML. Our TEI Boilerplate Demo illustrates many TEI features rendered by TEI Boilerplate.
Browser Compatibility
TEI Boilerplate requires a robust, modern browser to do its work. It is compatible with current versions of Firefox, Chrome, Safari, and Internet Explorer (IE 9). If you have problems with TEI Boilerplate with a modern browser, please let us know by filing a bug report at https://sourceforge.net/p/teiboilerplate/tickets/.
Rationale
TEI is a language designed primarily to express the content of documents. Projects that use TEI are responsible for developing their own methods of augmenting or converting it to a presentation-ready state for the web. Two potential paths to reach this goal are:
- Transforming TEI to HTML using XSLT. The output HTML is typically styled with CSS.
- Attaching a CSS stylesheet directly to the TEI XML.
Both of these approaches have advantages and disadvantages. While HTML is the
language of the web and, as such, is well supported browsers, its descriptive
capabilities are much less expressive than TEI. When TEI is transformed to HTML,
much of the richness of the TEI is lost or obscured in the resulting HTML.
However, the browser understands HTML very well and knows, for example, when to
initiate retrieval of a document based on certain user events, such as clicking
a link. The second option, CSS-styled TEI, allows for all of the TEI data to be
delivered directly to the browser. However, while the browser may apply CSS to
format and style a TEI document, the browser does not understand the semantics
of TEI. For instance, the browser does not understand that TEI's <ptr>
and
<ref>
elements are linking elements.
TEI Boilerplate bridges the gap between these two approaches by creating an environment in which TEI XML is delivered directly to browser, and styled by CSS. We accomplish this by making use of the built-in XSLT (1.0) capabilities of browsers to embed the TEI XML within a minimal HTML5 shell document. The TEI XML document is embedded, with minimal modifications, within this HTML5 shell. Features expected of web documents, such as clickable links and display of linked images, are enabled through selective transformation of a very small number of TEI elements and attributes.
TEI Boilerplate is not intended to be a replacement for the many excellent XSLT solutions for publishing and displaying TEI/XML on the web. It is intended to be a simple and lightweight alternative to more complex XSLT solutions. There are both practical and theoretical advantages to this lightweight approach.
Practical Benefits
XSLT is far more powerful than CSS and can manipulate XML documents in ways that CSS cannot. XSLT can radically transform documents and can combine multiple XML data sources into a single output file or multiple output files. But the power of XSLT comes at a cost. XSLT is a far more complex language than CSS and has a far steeper learning curve. There are relatively few expert XSLT programmers compared to the numbers of expert Web developers with extensive knowledge of HTML/CSS/JavaScript.
On the other hand, JavaScript is an extremely capable language for doing fancy things with XML content. JavaScript frameworks like JQuery and EXT JS, and the major browsers provide excellent support for manipulating the DOM (Document Object Model) of the web page. With TEI Boilerplate, the TEI document becomes part of the DOM, and JavaScript may then be used to perform more complex transformations, movements, and other manipulations of the TEI content than can be achieved with CSS alone. Our TEI Boilerplate Demo includes a simple example in the “Toolbox,” with a check box that uses JavaScript to hide and reveal the page breaks in a portion of the demo document.
TEI Boilerplate gives HTML/CSS/JavaScript documents direct access to original TEI content, and it gives TEI documents direct access to the substantial capabilities of HTML, CSS, and JavaScript—the dominant document format, styling language, and (client-side) programming language of the web. TEI Boilerplate aims for simplicity and elegance, but it also facilitates complexity and innovation by exposing TEI content directly to capabilities of JavaScript, the many powerful JavaScript frameworks, and CSS.
In teaching contexts, TEI Boilerplate may be a useful solution. Students and scholars new to TEI are rightly excited and enthused as they encode their first documents and experience the expressive power of TEI encoding. But too often that initial excitement and enthusiasm dissipates when new TEI users inquire about publishing their documents on the web and are confronted with sometimes overwhelming details about an unfamiliar programming language, XSLT, and other information about server side processing, transformation engines, and so on. With TEI Boilerplate, users can simply add a single line of code to their documents to allow modern browsers to produce formatted output of their TEI content. And that display may be further tweaked and customized using CSS.
TEI Boilerplate and Omeka
TEI Boilerplate is a simple solution for delivering TEI documents through Omeka. No additional software or plugins are necessary. One can simply simply host the TEI Boilerplate XSLT, JavaScript, and CSS files on a server (or as items in Omeka) and change any links to point to those online files.
Note: Some browsers apply the “same origin” security policy to XSLT stylesheets, which prohibits the use of XSLT from a different domain than the input document. For this reason, it is best to host the TEI Boilerplate files in the same domain as the Omeka installation.
Theoretical Advantages
The power of TEI lies in the richness and expressiveness of its vocabulary. But much of that richness and expressiveness is lost in the translation to HTML. TEI Boilerplate largely preserves the integrity of the TEI document. Since the original TEI document is delivered directly to the browser, the source TEI can be easily accessed and saved to the desktop or mobile device.
Scholars labor over the intricate encoding of TEI documents, encoding that may represent sophisticated readings and analysis. But with the typical XSLT publishing solution, which transforms the TEI to HTML, much or all of the richness of the TEI content is lost. Furthermore, the presentation of the document is targeted at the HTML surrogate rather than the intricately encoded TEI document. This results in a conceptual disconnect between the design of the document and the original TEI encoding. By exposing the TEI directly to the browser, one may format the TEI directly, applying intentional design to a sophisticated model of a source document. If one wishes to manipulate the document using JavaScript, one may manipulate the TEI directly. Scholars are likely to be intimately familiar with their TEI documents, and their engagement with and understanding of these documents may benefit when the formatting and processing is targeted at the TEI itself, rather than at an HTML surrogate.
TEI Boilerplate respects the integrity of the TEI document, and keeps the TEI document central throughout the publication process.
How It Works
When a TEI document using TEI Boilerplate is accessed by a browser, the browser
reads a line (the xml-stylesheet
processing instruction) in the file that
indicates that the XML should be processed by the TEI Boilerplate XSLT
stylesheet. The browser then processes the TEI according to the rules of the
stylesheet, which results in an HTML5 shell document within which the TEI
document is embedded. A very small number of TEI elements and attributes (e.g.
<ptr>
, <ref>
, <figure>
, and @rend
) are converted to their closest HTML
equivalents to enable features such as clickable links, display of images, and
support for inline CSS. The HTML shell contains a link to the TEI Boilerplate
CSS file, which tells the browser how to style the full document.
Using it in Your Project
Download the TEI Boilerplate
files, and host the
teibp
directory on a web server.
The simplest way to use TEI Boilerplate (TEIBP) is simply to add your TEI files
to the teibp/content
directory of TEI Boilerplate and include the following
xml-stylesheet processing instruction at the top of your TEI documents, after
the XML declaration and before the root <TEI>
element:
<?xml-stylesheet type="text/xsl" href="teibp.xsl"?>
You may then access your TEI files from a modern browser and see the resulting styled document.
TEI Boilerplate and CSS
TEI Boilerplate makes extensive use of CSS to generate styled documents in the browser. The CSS is drawn from three possible sources:
- External css stylesheets:
teibp.css
includes default styles for the HTML shell and TEI document.custom.css
is an empty stylesheet provided as a placeholder for user styles.
<rendition>
elements with@scheme="css"
within the TEI document are used to generate CSS declarations understood by the browser.- The global
@rend
attribute may be used to include inline CSS in TEI documents. The contents of@rend
are copied to@style
, which is understood by the browser.
Customizing the Look
TEI Boilerplate includes a default “theme” and some alternative themes. These are provided mostly as an illustration of TEI Boilerplate's capabilities. Users may modify these supplied themes in the following ways:
- By supplying
<rendition>
elements with@scheme="css"
within the<tagsDecl>
section of your TEI document. TEI Boilerplate will automatically convert the<rendition>
elements into CSS declarations in a<style>
element of the HTML5 shell that surrounds the TEI document after the simple XSLT transformation. TEI elements that use the@rendition
attribute to point to<rendition>
styles will be styled accordingly. This mechanism is similar to using HTML's@class
to point to CSS classes. See the TEI Guidelines for more details on<rendition>
and@rendition
. The TEI Boilerplate TEI template (teibp.xml) also includes examples. - By adding custom CSS to the
custom.css
file located in theteibp/css
directory. The HTML shell created by TEI Boilerplate includes a link to the custom.css file. This file is empty by default. You may add user styles to this file.
The TEI Boilerplate Template
An important component of TEI Boilerplate is a “boilerplate” TEI template (teibp.xml), a very simple TEI file, with some XML comments about where one might typically put basic information (e.g., title, author, bibliographic details of any source material). The most important features of the TEI Boilerplate template are:
- The
xml-stylesheet
processing instructions with links to the TEI Boilerplate XSLT and CSS files. - A pre-defined set of
<rendition>
elements with generally useful styles for describing a source document or for use in a born-digital TEI document. For instance, the template includes styles for bold, italicized, underlined, and “normal” text; for left-aligned, right-aligned, centered, and fully justified text; for indentation of verse lines; block quotes; and so on. These styles are discussed in more detail in a separate document: Styles available in the TEI Boilerplate Template
Users of TEI Boilerplate may choose to use the styles provided in the template,
and add to, modify, or replace them. As explained above, <rendition>
elements,
along with @rendition
and @rend
are all used by TEI Boilerplate to produced
styled documents in the browser. Thus, TEI authors may achieve substantial
results by using these standard TEI features, without the need to edit any of
the TEI Boilerplate code.
Downloads
Download the latest release of TEI Boilerplate from SourceForge: http://sourceforge.net/projects/teiboilerplate/files/.
People
The TEI Boilerplate team is:
- John Walsh, Indiana University
- Grant Simpson, Indiana University
- Saeed Moaddeli, Indiana University
Please send general feedback to John Walsh at jawalsh@indiana.edu. Bug reports and feature requests may be submitted through SourceForge: https://sourceforge.net/p/teiboilerplate/tickets/.