Change background image based on the hour [closed]

This question isn’t WordPress specific so is perhaps better for StackOverflow instead. We can make it WordPress specific by suggesting the use of wp_enqueue_script to add the script to the page, but ultimately this is a JavaScript question.

I’m basing my answer off of this article

// Get the local time of the visitor
var localTime = new Date();
var localHour = localTime.getHours();
            
// Bool to determine if it is night or day
var isNight = ( 18 <= localHour || 8 >= localHour ) ? true : false;
            
// Object containing URL links to images 
const  backgroundURLs = {
    day: 'https://placekitten.com/1960/1960',
    night: 'https://placekitten.com/1961/1961',
};
                
// Sets the background image
const setBackground = (image) => {
  // wait for window to be loaded to ensure body is present, 
  // if you are checking this elsewhere you can remove the window.onload check
  window.onload = function() {
     document.body.style.background = "url('"+backgroundURLs[image]+"')";
  }
};
            
// Actually set the background based on the bool and URL object. 
if ( isNight ) {
  setBackground('night');
} else {
  setBackground('day');
}