Extracting Structure from HTML using Adam's dom.d

["Nordlöw" via Digitalmars-d-learn]

On Thursday, 22 January 2015 at 02:06:16 UTC, Adam D. Ruppe wrote:
> You can do that with a CSS selector like:
>
> document.querySelector("#H2_A + p");

What is the meaning of selectors such as

     `a[href]`

used in

     doc.querySelectorAll(`a[href]`)

?