javascript – I need to remove the video in the background by pressing the button JS

const backVideo = document.querySelector("video");
var videoButton = document.getElementById("VideoOf")
var videoButtonOn = document.getElementById("VideoOn")

function videoOf() {
  backVideo.style.opacity = "0"
  if (backVideo.style.opacity = "0"){
    videoButton.style.opacity = "0"
    videoButtonOn.style.opacity = "1"
    
  } 
}
function videoOn() {
  backVideo.style.opacity = "1"
  if(backVideo.style.opacity = "1"){
    videoButtonOn != null;
    videoButton.style.opacity = "1"
    videoButtonOn.style.opacity = "0"
  }
}