docs.js

$(document).ready(function() {
  $("a[data-class]").click(function() {
    updateNavbarClass($(this).attr("data-class"));
  });

  updateNavbarClass("navbar-fixed-left");
});

function updateNavbarClass(className) {
  $("nav")
    .removeClass(function(index, css) {
      return (css.match(/(^|\s)navbar-fixed-\S+/g) || []).join(" ");
    })
    .addClass(className);

  $("a[data-class]")
    .removeClass("active")
    .parent("li")
    .removeClass("active");
  $('a[data-class="' + className + '"]')
    .addClass("active")
    .parent("li")
    .addClass("active");

  fixBodyMargin(className);
}

function fixBodyMargin(className) {
  if (/navbar-fixed-(left|right)/.test(className)) {
    $("body").removeAttr("style");
    if (className === "navbar-fixed-right") {
      $("body").css("marginLeft", 0);
    } else {
      $("body").css("marginRight", 0);
    }
  } else {
    $("body").css({
      "margin-right": 0,
      "margin-left": 0,
      "padding-top": "70px"
    });
  }
}