1. DomName('Element.querySelectorAll')
ElementList<Element> querySelectorAll(String selectors)

Finds all descendent elements of this element that match the specified group of selectors.

selectors should be a string using CSS selector syntax.

var items = element.querySelectorAll('.itemClassName');

For details about CSS selector syntax, see the CSS selector specification.

Source 

@DomName('Element.querySelectorAll')
ElementList<Element /*=T*/> querySelectorAll/*<T extends Element>*/(String selectors) =>
  new _FrozenElementList/*<T>*/._wrap(_querySelectorAll(selectors));