javascript window onload finished code example

Example 1: window.onload execute after load page

/* javascript function is executed after 5 seconds page was loaded */
window.onload = function() {
   setTimeout(loadAfterTime, 5000)
}; 
 
function loadAfterTime(){
   document.getElementById("menu").style.display="block";
}

Example 2: how to trigger events when the document loads in js

document.addEventListener("DOMContentLoaded", ready);
function ready() {
    alert('DOM is ready');

    // image is not yet loaded (unless it was cached), so the size is 0x0
    alert(`Image size: ${img.offsetWidth}x${img.offsetHeight}`);
}