A simple jQuery function to add a class of 'active' to the current navigation. Great for all those one-pagers out there

HighlightCurrentNav.js

// Highlight Current Nav
$(document).ready(function() {
    // Declare vars
    var sections = $('section')
    var nav = $('nav')

    // When the window scrolls get the position 
    $(window).on('scroll', function() {
        var curPos = $(this).scrollTop();
        // An offset value based on window height
        var offset = $(window).height() / 3;

        // Get the top and bottom position of each section
        sections.each(function() {
            var top = $(this).offset().top - offset,
                bottom = top + $(this).outerHeight();
            // Conditional to work out if section is in correct place 
            if (curPos >= top && curPos <= bottom) {
                // Remove active class from nav items and sections
                nav.find('a').removeClass('active');
                sections.removeClass('active');
                // Add active class to current section and nav item
                $(this).addClass('active');
                nav.find('a[href="#' + $(this).attr('id') + '"]').addClass('active');
            }
        });
    });
});