jquery.viewport-original.js

/*
 * Viewport - jQuery selectors for finding elements in viewport
 *
 * Copyright (c) 2008-2009 Mika Tuupola
 *
 * Licensed under the MIT license:
 *   http://www.opensource.org/licenses/mit-license.php
 *
 * Project home:
 *  http://www.appelsiini.net/projects/viewport
 *
 */
(function($) {
    
    $.belowthefold = function(element, settings) {
        var fold = $(window).height() + $(window).scrollTop();
        return fold <= $(element).offset().top - settings.threshold;
    };

    $.abovethetop = function(element, settings) {
        var top = $(window).scrollTop();
        return top >= $(element).offset().top + $(element).height() - settings.threshold;
    };
    
    $.rightofscreen = function(element, settings) {
        var fold = $(window).width() + $(window).scrollLeft();
        return fold <= $(element).offset().left - settings.threshold;
    };
    
    $.leftofscreen = function(element, settings) {
        var left = $(window).scrollLeft();
        return left >= $(element).offset().left + $(element).width() - settings.threshold;
    };
    
    $.inviewport = function(element, settings) {
        return !$.rightofscreen(element, settings) && !$.leftofscreen(element, settings) && !$.belowthefold(element, settings) && !$.abovethetop(element, settings);
    };
    
    $.extend($.expr[':'], {
        "below-the-fold": function(a, i, m) {
            return $.belowthefold(a, {threshold : 0});
        },
        "above-the-top": function(a, i, m) {
            return $.abovethetop(a, {threshold : 0});
        },
        "left-of-screen": function(a, i, m) {
            return $.leftofscreen(a, {threshold : 0});
        },
        "right-of-screen": function(a, i, m) {
            return $.rightofscreen(a, {threshold : 0});
        },
        "in-viewport": function(a, i, m) {
            return $.inviewport(a, {threshold : 0});
        }
    });

    
})(jQuery);

jquery.viewport.js

/*
 * Viewport - jQuery selectors for finding elements in viewport
 *
 * Copyright (c) 2008-2009 Mika Tuupola
 *
 * Licensed under the MIT license:
 *   http://www.opensource.org/licenses/mit-license.php
 *
 * Project home:
 *  http://www.appelsiini.net/projects/viewport
 *
 * Clean up by Rick Waldron, 2010
 * 
 * Includes: 
 * 
 * - Consolidation of functions into single fn namespace
 * - Filter functions declared within an object
 * - caching of multiple repetitive $(window) calls to $window
 * - caching of multiple repetitive $(element) calls to $element
 *
 */
(function($) {
    
    //  declare and assign a single fn namespace
    $.viewport  = function ( expr, element, settings ) {
      // privately declare all custom viewport fns
      var viewables = {
        belowthefold: function(element, settings) {
          var $window = $(window), 
              fold    = $window.height() + $window.scrollTop();
          
          return fold <= $(element).offset().top - settings.threshold;
        }, 
        abovethetop: function(element, settings) {
          var $window   = $(window),
              $element  = $(element), 
              top       = $window.scrollTop();
              
          return top >= $element.offset().top + $element.height() - settings.threshold;
        }, 
        rightofscreen: function(element, settings) {
          var $window   = $(window),
              $element  = $(element), 
              fold      = $window.width() + $window.scrollLeft();
              
          return fold <= $element.offset().left - settings.threshold;
        }, 
        leftofscreen: function(element, settings) {
          var $window   = $(window),
              $element  = $(element), 
              left      = $window.scrollLeft();
              
          return left >= $element.offset().left + $element.width() - settings.threshold;
        }, 
        inviewport: function(element, settings) {
          return !$.viewport('rightofscreen', element, settings) && 
                  !$.viewport('leftofscreen', element, settings) && 
                    !$.viewport('belowthefold', element, settings) && 
                      !$.viewport('abovethetop', element, settings);
        }
      };
      
      if ( viewables[expr] && $.isFunction(viewables[expr]) ) {
        return viewables[expr].call(this, element, settings);
      }
    };    

    
    $.extend($.expr[':'], {
      "below-the-fold": function(a, i, m) {
        return $.viewport('belowthefold', a,  {threshold : 0});
      },
      "above-the-top": function(a, i, m) {
        return $.viewport('abovethetop', a,  {threshold : 0});
      },
      "left-of-screen": function(a, i, m) {
        return $.viewport('leftofscreen', a,  {threshold : 0});
      },
      "right-of-screen": function(a, i, m) {
        return $.viewport('rightofscreen', a,  {threshold : 0});
      },
      "in-viewport": function(a, i, m) {
        return $.viewport('inviewport', a,  {threshold : 0});
      }
    });

})(jQuery);