Why onload is set to null in responsiveImageWithPlaceholder.blade.php

[kallepyorala]

I did simple image carousel with Livewire and only way to get responsive images to work was to change responsiveImageWithPlaceholder.blade.php from this

onload="this.onload=null;this.sizes=Math.ceil(this.getBoundingClientRect()...

to this:

onload="this.sizes=Math.ceil(this.getBoundingClientRect()...

So my code works, but I would like to understand why this.onload=null is there and what I might break by removing it.