**If statement in jQuery example:**

    if (n < 2) {
    		$("body").css("background", "green");
    	} 

**I noticed your if statement is missing curly brackets `{  }` so try** 

    (function ($) {
        
      $(document).ready(function() {
         $("#second-column").on("swipe",function(){
               if($(window).width()<=900) {
               $("#nice-menu-1>li>ul").css("display: block; visibility: visible;"); 
               }           
            });
        });
            
    })(jQuery);