!function($){'use strict'
var Class=function(el,cb){this.$el=$(el);this.cb=cb;this.watch();return this;};Class.prototype={isIn:function isIn(){var _self=this;var $win=$(window);var elementTop=_self.$el.offset().top;var elementBottom=elementTop+_self.$el.outerHeight();var viewportTop=$win.scrollTop();var viewportBottom=viewportTop+$win.height();return elementBottom>viewportTop&&elementTop<viewportBottom;},watch:function(){var _self=this;var _isIn=false;$(window).on('resize scroll',function(){if(_self.isIn()&&_isIn===false){_self.cb.call(_self.$el,'entered');_isIn=true;}if(_isIn===true&&!_self.isIn()){_self.cb.call(_self.$el,'leaved');_isIn=false;}})}};$.fn.isInViewport=function(cb){return this.each(function(){var $element=$(this);var data=$element.data('isInViewport');if(!data){$element.data('isInViewport',(new Class(this,cb)));}})}}(window.jQuery);