To use querySelector with IDs that are numbers in JavaScript, we have to escape the unicode code point representation of the number.
For instance, we can write:
<div id='1'>
hello world
</div>
Then we write:
const el = document.querySelector('#\\31');
console.log(el)
to select the div with ID 1.
U+0031 is the Unicode code point of the character 1, so we pass in \31 , which is the escaped version of the Unicode code point representation of 1.
el should be the div with ID 1 as a result.
