Original Envy child theme main.js, by Jon Barratt

main.js

jQuery(document).ready(function($) {	


	// Responsive menu items:
	$('.nav-header .genesis-nav-menu').before('<li class="menu-icon"></li>');

	$(".menu-icon").on("click", function(){
		$(".nav-header .genesis-nav-menu").slideToggle();
	});
	
	
	// Declare variables for heights:
	var topnavHeight, sliderHeight, headerHeight
	
	
	// Calculate variables and size of displacements:
	$(window).on("load resize", function() {
		
		// Menu reset before calculating heights:
		$(".nav-header .genesis-nav-menu").hide();
		
		// Assign values to variables:
		topnavHeight = $(".nav-secondary").outerHeight() || 0;
		sliderHeight = $(".slides li").outerHeight() || 0;
		headerHeight = $(".site-header").height();
	
	});
		

	// Determine header position and displacements:
	$(window).on("load scroll resize", function() {
		
		var scrollYpos = $(document).scrollTop()
		var windowWidth = $(window).width()
		
		// Media query to detect slider onscreen for window size > 960 pixels:
		if (windowWidth > 960 && $(".home-slider").length > 0 && scrollYpos < sliderHeight - 5) {
			
			// Set displacements in flow:
			$(".site-container").css('padding-top',topnavHeight);
			$(".home-slider").css('margin-bottom',headerHeight);
				
			// Unstick header and make header full height:
			$(".site-header").addClass('unstuck').css('top',sliderHeight + topnavHeight);
			$(".site-header .wrap").removeClass('narrow');			
			
			return false
			
		} else {
			
			// Set displacements in flow:
			$(".site-container").css('padding-top',topnavHeight + headerHeight);
			$(".home-slider").css('margin-bottom', 0);
			
			// Make header sticky:
			$(".site-header").removeClass('unstuck').css('top',topnavHeight);
			
			// Make header narrow on scroll:
			if (windowWidth > 960 && scrollYpos > 5) {
				$(".site-header .wrap").addClass('narrow');
			} else {
    			$(".site-header .wrap").removeClass('narrow');	
			}
			
		}
			
	});
	
	
	// Fade out store notice soon after page load:
	$(".demo_store").delay(4000).slideUp();
	
	
});