save a transcript of KhanAcademy's video

gistfile1.txt

const spans = $("ul[itemprop=transcript] li span[class='']");
const array = Array.from(spans);
const texts = array.map(t => t.textContent.replace(/\n/, '') + '\n');

const fileName = $("h1")[0].textContent;
const file = new File(texts, fileName, {
  type: "text/plain",
});

const a = document.createElement("a");
a.href = URL.createObjectURL(file);
a.download = fileName;
a.click();