Are they all checked?

Simplest way to check whether all checkbox input fields checked or not; by converting a NodeList to an Array using ES6 ... spread operator so we can attach every() method to it;

Checkout the Are they all checked? Demo on jsfiddle

[...document.querySelectorAll('input')].every(checkbox => checkbox.checked)

Comments

[Mahmoud Elmahdi]

Thanks Arden! You can definitely do the same thing with Array.from, but in my case, the ... is better use IMO. Less code, easy to remember, plus performance. Cheers

[JavaScript Joel]

Also

Array.prototype.every.call(document.querySelectorAll('input'), checkbox => checkbox.checked)