The syntax of individual documents in WWW hypertext is specified in Hypertext Markup Language (HTML)
HTML is a specific application of the Standard Generalized Markup Language (SGML)
These introductions should be consulted for definitions of HTML syntax and, possibly, hints on HTML use.
There is no general convention for specifying larger hypertext structures in the WWW, however. This is a complicated matter, and for completeness would need to take browser and server properties into account as well as the properties of the text. HTML itself is located, within the model presented above, at the intermetdiate level of layout.
A hypertext in the WWW environment may be a single page-file containing a document whose layout syntax is specified in HTML (or is plain text), with links between parts of the text on the page, or it may be a collection of pages linked as a tree or a graph, with links pointing to other page-files or to a graphics file or to a Java application.