When to use "window.onload"?

javascript, onload, onload-event

Solution

`window.onload` just runs when the browser gets to it.

`window.addEventListener` waits for the window to be loaded before running it.

In general you should do the second, but you should attach an event listener to it instead of defining the function. For example:

window.addEventListener('load', 
  function() { 
    alert('hello!');
  }, false);

Problem

In JavaScript, when I want to run a script once when the page has loaded, should I use `window.onload` or just write the script? For example, if I want to have a pop-up, should I write (directly inside the `<script>` tag): ``` alert("hello!"); ``` Or: ``` window.onload = function() { alert("hello!"); } ``` Both appear to run just after the page is loaded. What is the the difference?

Original source

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