MiniVend allows you to debug your page HTML with an external page checking program. Because leaving this enabled on a production system is potentially a very bad performance degradation, the program is set in a the global configuration file with the CheckHTML directive.
To check a page for validity, set the global directive CheckHTML to the name of the program (don't do any output redirection). A good choice is the freely available program weblint -- it would be set in minivend.cfg with:
CheckHTML /usr/local/bin/weblint -s -
Of course you must restart the server for it to be recognized. The full path to the program should be used -- if you have trouble, check it from the command line (as you should with all external programs called by MiniVend).
Insert [tag flag checkhtml][/tag] at the top or bottom of pages you want to check, and the output of your
checker should be appended to the browser output as a comment, visible if
you view the page or frame source.
To do this only at times, use a Variable setting:
Variable CHECK_HTML [tag flag checkhtml][/tag]
and place __CHECK_HTML__ in your pages. You can then set the Variable to the empty string if you wish to disable it.