Download mp3 vk.com

// ==UserScript==
// @name        Download mp3 vk.com
// @include     https://vk.com/*
// @include     http://vk.com/*
// @grant       GM_xmlhttpRequest
// ==/UserScript==
var parseExt=S=>(S=/^[^?]+([.]\w+)[?]/.exec(S))? S[1]: '.mp3',
Save = (Url, Name, isOK)=>{
  if(!Url || !Name || !isOK) return;
  var A;
  (A = document.createElement('A')).href = Url;
  A.download = Name.replace(/[^а-я\x21-\x7e\s\w]/gi,"-").replace(/[\/\\\:\*\?"<>\|\&]+/g, "-");
  document.body.appendChild(A).click(); document.body.removeChild(A);
},
GetFromServer = (link, name)=>GM_xmlhttpRequest({
    method: "GET",
    responseType: 'blob',
    overrideMimeType: 'text/plain; charset=x-user-defined',
    url: link,
    onload: R=>Save(window.URL.createObjectURL(R.response), name, R.status==200)
});
window.addEventListener('contextmenu', e=>{
  if (!e.ctrlKey) return; e.preventDefault();
  var link, info, a = e.target;
  while (!a.classList.contains('audio') && (a=a.parentNode)) if(a==document.body) return;
  link = a.querySelector('[id^="audio_info"]').value;
  info = a.getElementsByClassName('title_wrap')[0];
  GetFromServer(link, info.textContent.trim() + parseExt(link));
});