Get VueJS __vue__ in chrome extension [duplicate]

Question

Good afternoon.

I try to do a chrome extension that need to access the main vue object on a Vue.js website. To do that, I type let vue=document.getElementById('app').__vue__ in chrome's console, and I can well read its values. In my chrome extension I have a script that contains exactly the same code but vue is undefined. I tried to debug like that.

let app=document.getElementById('app')
let vue=app.__vue__
console.log(app, vue)

the result is 'app=<div...> vue=undefined'. When I right click on app -> store as global variable (its often called temp1), and I do temp1.__vue__ then the result is not undefined and contains the object I was looking for (as if I wrote let vue=document.getElementById('app').__vue__).

Since my skills in web technologies are very bad, I would greatly appreciate a little help in figuring out what is going on and solving this problem. Thanks in advance !

Best