code: public static boolean contains(String url, String markup, String selector, String value) {
          ensureMarkup(url, markup);
          Document document = documents.get(url);
          Elements elements = document.select(selector);
          return elements.outerHtml().contains(value);
      }
docs: Checks if any of the elements from the {@code markup} identified by the {@code selector} contain the text from {@code value}. The
  {@code url} is used only for caching purposes, to avoid parsing multiple times the markup returned for the same resource.
  
  @param url      the url that identifies the markup
  @param markup   the markup
  @param selector the selector used for retrieval
  @param value    the text that should exist in the markup
  @return {@code true} if the {@code value} was found in the markup, {@code false} otherwise