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JavaScript AJAX Basics Programming AJAX Programming AJAX Challenge

Posted by Kirt Perez
Kirt Perez
7,374 Points

document.getElementById('roomList') returns a null. Is it wrong to use DOMContentLoaded to fix it?

https://w.trhou.se/20cq5t0t80

Hello all, in my attempt I was trying to get the div with the id "roomList" but it was returning null. After some searching, I learned that the javascript file is being ran before the HTML is fully loaded. As a fix I implemented an event listener with DOMContentLoaded and it fixed it. Is this a bad solution?

1 Answer

Martin Balon
Martin Balon
43,433 Points
Martin Balon
Martin Balon
43,433 Points

Hi Kirt, If you want to keep your script inside <head> I would suggest using keyword defer. This will run your script after DOM is loaded. https://www.w3schools.com/tags/att_script_defer.asp

<script src="js/widget.js" defer></script>

You could also move your script right above the closing body tag - the effect is the same.

I have also notice in react and vue that they put their scripts in the <head> with preload and then same scripts before closing body tag with keyword defer. I guess they preload them while html and css is rendering so they can run them immediately afterwards. Just open facebook in developer tools and see what I mean.

Kirt Perez
Kirt Perez
7,374 Points

Hmm, if I can recall, there was some reason as to why the teacher used the script tag in the head in one of these videos. All this time I was used to putting at the end of the closing body tag but seeing that this is a solution, I feel like I should just stick to that way fully.