xhtml_ns//2

Documentation
- Reference manual
- Packages
  - SWI-Prolog HTTP support
    - The HTTP server libraries
      - The library(http/html_write) library
        
        Repositioning HTML for CSS and javascript links
        
        html_post//2
        
        html_receive//1
        
        html_receive//2
        
        xhtml_ns//2

Availability::- use_module(library(http/html_write)).

xhtml_ns(+Id, +Value)//

Demand an xmlns:id=Value in the outer html tag. This uses the html_post/2 mechanism to post to the xmlns channel. Rdfa (http://www.w3.org/2006/07/SWD/RDFa/syntax/), embedding RDF in (x)html provides a typical usage scenario where we want to publish the required namespaces in the header. We can define:

rdf_ns(Id) -->
        { rdf_global_id(Id:'', Value) },
        xhtml_ns(Id, Value).

After which we can use rdf_ns//1 as a normal rule in html//1 to publish namespaces from library(semweb/rdf_db). Note that this macro only has effect if the dialect is set to xhtml. In html mode it is silently ignored.

The required xmlns receiver is installed by html_begin//1 using the html tag and thus is present in any document that opens the outer html environment through this library.