const year = new Date();

const copyListener = (event) => {

  const range = window.getSelection().getRangeAt(0),

    rangeContents = range.cloneContents(),

    info = `© ${year.getFullYear()} LIGMATV`,

    helper = document.createElement("div");

​

  helper.appendChild(rangeContents);

​

  event.clipboardData.setData("text/plain", `${helper.innerText}\n${info}`);

  event.clipboardData.setData("text/html", `${helper.innerHTML}<br>${info}`);

  event.preventDefault();

};

document.addEventListener("copy", copyListener);