Fixed menu (a selector) when the page scrolls

Fixed menu jQuery

//common.js
$(function() {
	$(window).scroll(function() { 
		var the_top = $(document).scrollTop();
		if (the_top > 1) {
			$('.site-navigation-wrap').addClass('fixed-menu');
		}
		else {
			$('.site-navigation-wrap').removeClass('fixed-menu');
		}
	});
});

//index.html
<div class="site-navigation-wrap"></div>

//style.sass

.site-navigation-wrap
	min-height: 48px
	background: $headers-color
	position: relative

.fixed-menu
  position: fixed
  top: 0
  left: 0
  right: 0
  margin: 0
  z-index: 500