// assumes jquery is used with $(...)
sbool jqueryUsed(S html) {
  if (cic(getHTMLComments(html), "needs jquery")) true;
  if (!regexpFind("\\$\\s*\\(", html)) false;
  for (S script : allJavascriptFromHTMLIncludingEventHandlers(html))
    if (jcontains(jsTok(script), "$(")) true;
  false;
}