Simply add a "Download Mp3" link to send url to http://www.youtube-mp3.org/it
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/7725/33765/YouTube%20mp3%20download%20with%20youtube-mp3org.js
// ==UserScript==
// @name YouTube mp3 download with youtube-mp3.org
// @namespace Restpeace
// @description Simply add a "Download Mp3" link to send url to http://www.youtube-mp3.org/it
// @include http://*youtube.*/*watch*
// @include https://*youtube.*/*watch*
// @version 1.0
// @author Restpeace
// ==/UserScript==
// ==ChangeLog==
// @history 1.0 Updated headers.
// ==/ChangeLog==
var video=window.location.href;
var newLink = document.createElement("a");
newLink.setAttribute('href', "http://www.youtube-mp3.org/it?youtube-url="+video);
newLink.setAttribute('target', "_blank");
newLink.innerHTML = 'Mp3 Download';
var b1=document.getElementById("watch8-secondary-actions");
var b2=document.getElementsByClassName("yt-uix-menu")[0];
if(b1){
b1.appendChild(newLink);
}else{
b2.appendChild(newLink);
}