Template:Peking/Javascript/jquery sticky

// Sticky Plugin // ============= // Author: Anthony Garand // Improvements by German M. Bravo (Kronuz) and Ruud Kamphuis (ruudk) // Improvements by Leonardo C. Daronco (daronco) // Created: 2/14/2011 // Date: 2/12/2012 // Website: http://labs.anthonygarand.com/sticky // Description: Makes an element on the page stick on the screen as you scroll // It will only set the 'top' and 'position' of your element, you // might need to adjust the width in some cases.

(function($) {

   var defaults = {
           topSpacing: 0,
           bottomSpacing: 0,
           className: 'is-sticky',
           wrapperClassName: 'sticky-wrapper'
       },
       $window = $(window),
       $document = $(document),
       sticked = [],
       windowHeight = $window.height(),
       scroller = function() {
           var scrollTop = $window.scrollTop(),
               documentHeight = $document.height(),
               dwh = documentHeight - windowHeight,
               extra = (scrollTop > dwh) ? dwh - scrollTop : 0;
           for (var i = 0; i < sticked.length; i++) {
               var s = sticked[i],
                   elementTop = s.stickyWrapper.offset().top,
                   etse = elementTop - s.topSpacing - extra;
               if (scrollTop <= etse) {
                   if (s.currentTop !== null) {
                       s.stickyElement
                           .css('position', )
                           .css('top', )
                           .removeClass(s.className);
                       s.stickyElement.parent().removeClass(s.className);
                       s.currentTop = null;
                   }
               }
               else {
                   var newTop = documentHeight - s.stickyElement.outerHeight()
                       - s.topSpacing - s.bottomSpacing - scrollTop - extra;
                   if (newTop < 0) {
                       newTop = newTop + s.topSpacing;
                   } else {
                       newTop = s.topSpacing;
                   }
                   if (s.currentTop != newTop) {
                       s.stickyElement
                           .css('position', 'fixed')
                           .css('top', newTop)
                           .addClass(s.className);
                       s.stickyElement.parent().addClass(s.className);
                       s.currentTop = newTop;
                   }
               }
           }
       },
       resizer = function() {
           windowHeight = $window.height();
       },
       methods = {
           init: function(options) {
               var o = $.extend(defaults, options);
               return this.each(function() {
                   var stickyElement = $(this);

                   stickyId = stickyElement.attr('id');

wrapper = $('

')

                       .attr('id', stickyId + '-sticky-wrapper')
                       .addClass(o.wrapperClassName);
                   stickyElement.wrapAll(wrapper);
                   var stickyWrapper = stickyElement.parent();
                   stickyWrapper.css('height', stickyElement.outerHeight());
                   sticked.push({
                       topSpacing: o.topSpacing,
                       bottomSpacing: o.bottomSpacing,
                       stickyElement: stickyElement,
                       currentTop: null,
                       stickyWrapper: stickyWrapper,
                       className: o.className
                   });
               });
           },
           update: scroller
       };

   // should be more efficient than using $window.scroll(scroller) and $window.resize(resizer):
   if (window.addEventListener) {
       window.addEventListener('scroll', scroller, false);
       window.addEventListener('resize', resizer, false);
   } else if (window.attachEvent) {
       window.attachEvent('onscroll', scroller);
       window.attachEvent('onresize', resizer);
   }

   $.fn.sticky = function(method) {
       if (methods[method]) {
           return methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
       } else if (typeof method === 'object' || !method ) {
           return methods.init.apply( this, arguments );
       } else {
           $.error('Method ' + method + ' does not exist on jQuery.sticky');
       }
   };
   $(function() {
       setTimeout(scroller, 0);
   });

})(jQuery);