jQuery determine if ul has class OR another one

You could use is instead?

if ($('#menu-item-49').is('.current-menu-item, .current-menu-parent')) {  $('ul.sub-menu ').css('display', 'block');}

Check the current matched set of elements against a selector and return true if at least one of these elements matches the selector.

Beats having to use multiple hasClass queries, which is the alternative:

if ($('#menu-item-49').hasClass('current-menu-item') ||     $('#menu-item-49').hasClass('current-menu-parent')) {  $('ul.sub-menu ').css('display', 'block');}

You cannot use the || (or) operator within hasClass. Try this:

if ($('#menu-item-49').hasClass('current-menu-item') ||     $('#menu-item-49').hasClass('current-menu-parent')) {  $('ul.sub-menu ').css('display', 'block');}

Or you can do this if that's too verbose:

var $menuItem = $('#menu-item-49');if ($menuItem.hasClass('current-menu-item') ||     $menuItem.hasClass('current-menu-parent')) {  $('ul.sub-menu ').css('display', 'block');}

Or even better:

var $menuItem = $('#menu-item-49');if ($menuItem.is('.current-menu-item, .current-menu-parent')) {  $('ul.sub-menu ').css('display', 'block');}

if ($('#menu-item-49').hasClass('current-menu-item') || $('#menu-item-49').hasClass('current-menu-parent') ) {  $('ul.sub-menu ').css('display', 'block');}

Have you tried the following?