From http://stackoverflow.com/questions/8383742/keeping-toggled-class-after-page-refresh

keeping-toggled-class-after-page-refresh.js

$(document).ready(function() {
    var body_class = $.cookie('body_class');
    if(body_class) {
        $('body').attr('class', body_class);
    }
    $("a#switcher").click(function() {
        $("body").toggleClass("alternate_body");
        $.cookie('body_class', $('body').attr('class'));
    });
});