I have an embedded app (that I made) that I would like to add a guided intro.js tour over, but I can't seem to get it to work. I have tried with embed, object and iframe.

Here is my code so far

var app = document.getElementById("app");
// #app is the embedded site
var doc = app.contentDocument.body.getElementById("header-menu");
// select inner DOM and select an element inside the inner dom #header-menu

introJs().setOptions({
  steps: [{
    title: 'Welcome',
    intro: 'Hello World! 👋' // this part works always
  },
  {
   element: doc, // once this part is added, intro.js stops working as a whole
   intro: '2nd slide'
  }
  ]
}).start();

Let me know if I'm doing anything wrong.