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JavaScript DOM Scripting By Example Improving the Application Code The DOMContentLoaded Event

Posted by babyoscar
babyoscar
12,929 Points

Couldn't you use "window.onload" instead?

Is there any downsides/upsides of using window.onload like

window.onload = function () {
  //code here
};

rather than doing

document.addEventListener('DOMContentLoaded', () => {
  //code here
});

? I feel like using "window.onload" is easier to type and uses less code to do the same thing.

1 Answer

Steven Parker
Steven Parker
229,783 Points
Steven Parker
Steven Parker
229,783 Points

For trivial cases, it probably makes no difference; but for more complex or evolving projects:

  • the DOMContentLoaded event fires before associated resources load, the load event fires after
  • you can only have one "onload", but you can attach multiple listeners to an event
  • using addEventListener is considered a coding "best practice".
babyoscar
babyoscar
12,929 Points

Oh, okay, thanks!