JS - pass info in GET not HTTP headers

intention is to
  avoid CORS preflight OPTIONS query
  because they are blocked on some nearby servers
  (blocking is to avoid info leakage and DoS..?)

also fix tap-poc to pick up @id||@name
  from the new place,
  (noting lack of API support)
JS - supply GET query data

accept GET query data from parents in DOM
encode it as JSON
  could also accept CGI-encoded,
  but I found the JSON decoding function first

decorate the test.html with a sprinkling
  unused in the CGI, but visible in %ENV
JS - version leapfrog