"querySelectorAll()" with multiple conditions in JavaScript

Is it possible to make a search by querySelectorAll() using multiple unrelated conditions? If yes, how? And, how to specify whether those are AND or OR criteria?

For example:

How to find all forms, ps and legends with a single querySelectorAll() call? Possible?

Is it possible to make a search by querySelectorAll using multiple unrelated conditions?

Yes, because querySelectorAll accepts full CSS selectors, and CSS has the concept of selector groups, which lets you specify more than one unrelated selector. For instance:

var list = document.querySelectorAll("form, p, legend");

...will return a list containing any element that is a form or p or legend.

CSS also has the other concept: Restricting based on more criteria. You just combine multiple aspects of a selector. For instance:

var list = document.querySelectorAll("div.foo");

...will return a list of all div elements that also (and) have the class foo, ignoring other div elements.

You can, of course, combine them:

var list = document.querySelectorAll("div.foo, p.bar, div legend");

...which means "Include any div element that also has the foo class, any p element that also has the bar class, and any legend element that's also inside a div."