window.onload vs document.onload

window.onload

• It is fired when the entire page loads, including its content (images, css, scripts, etc.)
• $(window).load()

document.onload

• It is fired when the DOM is ready which can be prior to images and other external content is loaded
• In general, document.onload event is fired before the window.onload
• $(document).ready()

Also Read:

1. Difference between async and defer attributes in script tags
2. JavaScript Promises - Visualized
3. Promise javascript examples
4. pseudo elements vs pseudo classes
5. css - align text to an image vertically