Example of a JS object with public/private methods

disco_duck.js

    // Utility for ducking Discovery under fixed agent navigation bars and ads
    var discoDuck = (function() {

      var _discoveryContainer = $("#discoveryContainer");
      var _proNavBarHeight = $("#navbarAgent").outerHeight();
      var _proCatcherHeight = $("#pro_catcher").outerHeight();
      var _adjustMarginTop = function(pixels, addOrRemove) {
        if(_discoveryContainer.length < 1) {
          return;
        }
        var currentMarginTop = _discoveryContainer.css("margin-top").replace("px", "");
        var newMarginTop;

        if(addOrRemove === "add") {
          newMarginTop = parseInt(currentMarginTop) + parseInt(pixels);
        } else {
          newMarginTop = parseInt(currentMarginTop) - parseInt(pixels);
        }
        _discoveryContainer.css('margin-top', newMarginTop);
      };

      // ᕕ( ⁰ ਊ ⁰ )ᕗ ♪♬
      return {
        duckProNavBar: function () {
          _adjustMarginTop(_proNavBarHeight, 'add');
        },
        unDuckProNavBar: function () {
          _adjustMarginTop(_proNavBarHeight, 'remove');
        },
        duckProCatcher: function () {
          _adjustMarginTop(_proCatcherHeight, 'add');
        },
        unDuckProCatcher: function () {
          _adjustMarginTop(_proCatcherHeight, 'remove');
        }
      };
    })();