Check page width then apply css in jquery

I am trying to get jQuery to check the window width on resize. If the window is greater than 960px I'd like to apply display: block; inline style to the class .main-navigation. This is what I have so far but I can't get the syntax right.

jQuery(window).resize(function($) {
  if ($(window).width() < 960) {
     document.getElementByClass(".main-navigation").style.display = 'block';
  }
 else {}
});