clojuscript version of requestFullscreen inspired from js code https://www.w3schools.com/jsref/met_element_requestfullscreen.asp

request_full_screen.cljs

(ns open-full-screen.core
  (:require[goog.object :as gobj]))

(defn open-full-screen
  "`element-id` is the string of the html element id of
  the element to be displayed in fullscreen"
  [element-id]  
  (let [e (.getElementById js/document element-id)]
    (cond
      (gobj/get e "requestFullscreen") (.requestFullscreen e)
      (gobj/get e "mozRequestFullScreen") (.mozRequestFullScreen e)
      (gobj/get e "webkitRequestFullscreen") (.webkitRequestFullscreen e)
      (gobj/get e "msRequestFullscreen") (.msRequestFullscreen e))))

(defn close-full-screen
  []
  (let [d js/document]
    (cond
      (gobj/get d "exitFullscreen") (.exitFullscreen d)
      (gobj/get d "mozCancelFullScreen") (.mozCancelFullScreen d)
      (gobj/get d "webkitExitFullscreen") (.webkitExitFullscreen d)
      (gobj/get d "msExitFullscreen") (.msExitFullscreen d))))