(function($){

    /**
* Copyright 2012, Digital Fusion
* Licensed under the MIT license.
* http://teamdf.com/jquery-plugins/license/
*
* @author Sam Sehnert
* @desc A small plugin that checks whether elements are within
* the user visible viewport of a web browser.
* only accounts for vertical position, not horizontal.
*/
    var $w = $(window);
    $.fn.visible = function(partial,hidden,direction){

        if (this.length < 1)
            return;

        var $t = this.length > 1 ? this.eq(0) : this,
            t = $t.get(0),
            vpWidth = $w.width(),
            vpHeight = $w.height(),
            direction = (direction) ? direction : 'both',
            clientSize = hidden === true ? t.offsetWidth * t.offsetHeight : true;

        if (typeof t.getBoundingClientRect === 'function'){

            // Use this native browser method, if available.
            var rec = t.getBoundingClientRect(),
                tViz = rec.top >= 0 && rec.top < vpHeight,
                bViz = rec.bottom > 0 && rec.bottom <= vpHeight,
                lViz = rec.left >= 0 && rec.left < vpWidth,
                rViz = rec.right > 0 && rec.right <= vpWidth,
                vVisible = partial ? tViz || bViz : tViz && bViz,
                hVisible = partial ? lViz || lViz : lViz && rViz;

            if(direction === 'both')
                return clientSize && vVisible && hVisible;
            else if(direction === 'vertical')
                return clientSize && vVisible;
            else if(direction === 'horizontal')
                return clientSize && hVisible;
        } else {

            var viewTop = $w.scrollTop(),
                viewBottom = viewTop + vpHeight,
                viewLeft = $w.scrollLeft(),
                viewRight = viewLeft + vpWidth,
                offset = $t.offset(),
                _top = offset.top,
                _bottom = _top + $t.height(),
                _left = offset.left,
                _right = _left + $t.width(),
                compareTop = partial === true ? _bottom : _top,
                compareBottom = partial === true ? _top : _bottom,
                compareLeft = partial === true ? _right : _left,
                compareRight = partial === true ? _left : _right;

            if(direction === 'both')
                return !!clientSize && ((compareBottom <= viewBottom) && (compareTop >= viewTop)) && ((compareRight <= viewRight) && (compareLeft >= viewLeft));
            else if(direction === 'vertical')
                return !!clientSize && ((compareBottom <= viewBottom) && (compareTop >= viewTop));
            else if(direction === 'horizontal')
                return !!clientSize && ((compareRight <= viewRight) && (compareLeft >= viewLeft));
        }
    };

   var addAnimation = function(element){
    $(element).each(function(i, el){
      var el = $(el);
      if (el.visible(true)) {
        el.removeClass('visible').addClass('animated'); 
      } 
    });
   }

   var checkVisible = function(element){
    $(element).each(function(i, el) {
      var el = $(el);
         if (el.visible(false)) {
        el.addClass("visible"); 
      } 
    });     
   }

   $(window).load(function(){
    checkVisible('.animate');
   });

   $(window).load(function(){
    addAnimation('.animate');
   });

   $(window).scroll(function(event) {
      addAnimation('.animate');
   });

})(jQuery);