load – not only HTML is loaded, but also all the external resources: images, styles etc. code example

Example: 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}`);
}