jquery - Do something if screen width is less than 960 px -

how can make jquery if screen width less 960 pixels? code below fires 2nd alert, regardless of window size:

if (screen.width < 960) {     alert('less 960'); } else {      alert('more 960'); } 

use jquery width of window.

if ($(window).width() < 960) {    alert('less 960'); } else {    alert('more 960'); }