(function($){var selectors=[];var check_binded=false;var check_lock=false;var defaults={interval:250,force_process:false};var $window=$(window);var $prior_appeared=[];function appeared(selector){return $(selector).filter(function(){return $(this).is(':appeared');});}
function process(){check_lock=false;for(var index=0,selectorsLength=selectors.length;index<selectorsLength;index++){var $appeared=appeared(selectors[index]);$appeared.trigger('appear',[$appeared]);if($prior_appeared[index]){var $disappeared=$prior_appeared[index].not($appeared);$disappeared.trigger('disappear',[$disappeared]);}
$prior_appeared[index]=$appeared;}}
function add_selector(selector){selectors.push(selector);$prior_appeared.push();}
$.expr[':'].appeared=function(element){var $element=$(element);if(!$element.is(':visible')){return false;}
var window_left=$window.scrollLeft();var window_top=$window.scrollTop();var offset=$element.offset();var left=offset.left;var top=offset.top;if(top+$element.height()>=window_top&&top-($element.data('appear-top-offset')||0)<=window_top+$window.height()&&left+$element.width()>=window_left&&left-($element.data('appear-left-offset')||0)<=window_left+$window.width()){return true;}else{return false;}};$.fn.extend({appear:function(options){var opts=$.extend({},defaults,options||{});var selector=this.selector||this;if(!check_binded){var on_check=function(){if(check_lock){return;}
check_lock=true;setTimeout(process,opts.interval);};$(window).scroll(on_check).resize(on_check);check_binded=true;}
if(opts.force_process){setTimeout(process,opts.interval);}
add_selector(selector);return $(selector);}});$.extend({force_appear:function(){if(check_binded){process();return true;}
return false;}});})(function(){if(typeof module!=='undefined'){return require('jquery');}else{return jQuery;}}());