Markup and HTML
•Documents contain many elements such as
•In order to produce a professional-looking document, all of these elements should each have a
consistent style (appearance)
-That is, all the chapter headings should have a unique style, all the sub headings should have
another unique style, and all the picture captions should have yet another unique style, and so
-Each style might have its own font, colour, size, indentation, and/or other physical attributes
•What if you need to change one of these styles?
E.g. You are publishing the document in different-sized formats
You need different styles for different customers – for different languages/ cultures, for people
with disabilities (e.g. large-print books)
•How could you make this kind of change?
•How are you going to change the style of each element?
-If the document is small, you could manually modify each element, one-by-one
-If the document is large, this will become tedious and impractical
•The problem here is that the content and the appearance of the document are intertwined
•Content is the substance of a document. It consists of two main things:
-The text (that is, the words)
-The purpose of the words (are they chapter headings? paragraphs? footnotes?)
•Appearance is what the document looks like
-Fonts, colours, spacing, etc.
•In general, when you make a document (e.g. in Word), the content and appearance of the
document are usually intertwined
•It is much easier to change the overall style of a document if we separate the content from the
•In order to do this, we have to write the content in one part of the document, and write the
appearance in another part of the document (or in another document altogether)