converting observable viewof operator to normal js

Hi there!
Can someone please tell me how can I implement viewof operator in normal js.
I can’t use observable everywhere on a website so please help me.

A cell declaration like viewof n = … creates two variables: viewof n, which is just a regular DOM element (and is the thing you see in the cell), and n, which refers to the value property of the DOM element and is updated when the DOM element fires an input event.

// the DOM element
const n = document.querySelector("input")

// listening for and logging new values
n.addEventListener("input", e => console.log(e.currentTarget.value));