code: function emitSimpleTag() {
      if (nextchar === numchars) { return false; /* not even 1 char left */ }
      SIMPLETAG.lastIndex = nextchar;
      var matched = SIMPLETAG.exec(chars);
      if (!matched) throw new Error("should never happen");
      var tagname = matched[2];
      if (!tagname) return false;
      var endtag = matched[1];
      if (endtag) {
        nextchar += (tagname.length+2);
        insertToken(ENDTAG, tagname);
      }
      else {
        nextchar += (tagname.length+1);
        lasttagname = tagname;
        insertToken(TAG, tagname, NOATTRS);
      }
      return true;
    }
docs: A shortcut: look ahead and if this is a open or close tag in lowercase with no spaces and no attributes, just emit it now.