code: public static HtmlTree SPAN(HtmlStyle styleClass, Content body) {
          HtmlTree htmltree = new HtmlTree(HtmlTag.SPAN, nullCheck(body));
          if (styleClass != null)
              htmltree.addStyle(styleClass);
          return htmltree;
      }
docs: Generates a SPAN tag with style class attribute and some content.
  
  @param styleClass style class for the tag
  @param body content for the tag
  @return an HtmlTree object for the SPAN tag