CodeRunner Documentation (V3.2.1)
10.2 HTML formatted columns
As a special case, a format
%h means that the test result field should be taken as ready-to-output
HTML and should not be subject to further processing; this can be useful
with custom-grader templates that generate HTML output, such as
SVG graphics, and we have also used it in questions where the output from
the student's program was HTML.
%h format requires PHP >= 5.4.0 and Libxml >= 2.7.8 in order to
parse and clean the HTML output.