Sangam / Insta Video Downloader

// ==UserScript==
// @name         Insta Video Downloader
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       Sangam
// @match        https://www.instagram.com/*
// @grant        none
// @require http://code.jquery.com/jquery-3.3.1.min.js
// @license MIT
// ==/UserScript==

(function () {
  'use strict';
  // Your code here...
  function checkForContent(selector) {
    const tags = document.body.querySelectorAll(selector);
    console.log(tags)
    for (let i = 0; i < tags.length; i++) {
      const tag = $(tags[i]);
      console.log(tag.offset().top + tag.height() >= 0)
      console.log(tag.offset().top <= window.innerHeight)
      if (tag.offset().top + tag.height() >= 0 && tag.offset().top <= window.innerHeight) return tag.attr("src");
    }
    return null;
  }

  function getContentLink(e) {
    return checkForContent("video source") || checkForContent("video");
  }

  function downloadVideo() {
    const link = getContentLink();
    if (link == null) return alert("No video found");
    window.open(link)
  }
  const $body = $("body");
  $body.append(`<div id="downloader-icon" draggable="true" style="position:fixed; bottom: 40px; right: 20px; background-image: linear-gradient(#f99a52,#db579d); font-weight:bold; color:white; cursor:pointer; z-index:100000; padding: 5px 10px; border-radius:5px; box-shadow: 0 0 5px black">Search & Download</div>`);
  const $icon = $("#downloader-icon");
  $icon.click(downloadVideo);
})();