code: function getZhuyinHTML( rt ) {
    // #### Explanation ####
    // * `zhuyin`: the entire phonetic annotation
    // * `yin`:    the plain pronunciation (w/out tone)
    // * `diao`:   the tone
    // * `len`:    the length of the plain pronunciation (`yin`)
    var zhuyin = typeof rt === 'string' ? rt : rt.textContent
    var yin, diao, len
  
    yin  = zhuyin.replace( TYPESET.zhuyin.diao, '' )
    len  = yin ? yin.length : 0
    diao = zhuyin
      .replace( yin, '' )
      .replace( /[\u02C5]/g, '\u02C7' )
      .replace( /[\u030D\u0358]/g, '\u0307' )
    return len === 0 ? '' : '<h-zhuyin length="' + len + '" diao="' + diao + '"><h-yin>' + yin + '</h-yin><h-diao>' + diao + '</h-diao></h-zhuyin>'
  }
docs: Create a Zhuyin-form HTML string