I am trying to select a class with a specific attribute in JavaScript, as below:

var me = document.querySelector('.tab-content[data-tab=1]');

But getting the following error:

Uncaught DOMException: Failed to execute 'querySelector' on 'Document': '.tab-content[data-tab=1]' is not a valid selector.

I tried to change it to jQuery:

$('.tab-content[data-tab=1]')

Then it will work.

I tried to change it by adding double quotes:

var me = document.querySelector('.tab-content[data-tab="1"]');

Then it will also work.

I checked the attribute selector at W3 Schools and in its samples, there are [target=_blank], which does not require double quotes.

So why does removing double quotes not work for JavaScript?