Gleam:

import gleam/io

@external(javascript, "./js.js", "stringMe")
pub fn string_me() -> String

pub fn main() -> Nil {
  io.println(string_me())
}

JS:

export function stringMe() {
	return document.getElementById("input").value;
}

Compiled Gleam:

import * as $io from "../gleam_stdlib/gleam/io.mjs";
import { stringMe as string_me } from "./js.js";

export { string_me };

export function main() {
  return $io.println(string_me());
}

And $io.println() is just console.log.