:- use_module(library(http/html_write)). [det]html_post(+Id, 
:HTML)
[det]html_post(+Id, 
:HTML)//\-commands are executed by mailman/1 
from print_html/1 or html_print_length/2. 
These commands are called in the calling context of the html_post//2 
call.
A typical usage scenario is to get required CSS links in the document head in a reusable fashion. First, we define css//1 as:
css(URL) -->
        html_post(css,
                  link([ type('text/css'),
                         rel('stylesheet'),
                         href(URL)
                       ])).
Next we insert the unique CSS links, in the pagehead using the following call to reply_html_page/2:
        reply_html_page([ title(...),
                          \html_receive(css)
                        ],
                        ...)