mike-js-helpers.js

(function($){

	$.fn.isInViewport = function(){
		var elementTop = $(this).offset().top;
		var elementBottom = elementTop + $(this).outerHeight();
		var viewportTop = $(window).scrollTop();
		var viewportBottom = viewportTop + $(window).height();
		return (elementBottom > viewportTop && elementTop < viewportBottom);
	};
	
	$.fn.youTubeImage = function(){
		this.each(function(){
			var src = $(this).find('iframe').attr('title'); //.attr('src')
			var arr = src.split('/');
			
			if(typeof arr[2] != 'undefined'){
				if(arr[2].indexOf('youtube')+1){
					$(this).addClass('is-youtube');
				}
			}
			
			if(arr.length){
				var id = arr[arr.length-1].replace(/^(.*)\?(.*)$/, '$1');
				var image = 'http://img.youtube.com/vi/' + id + '/0.jpg';
				$(this).css({backgroundImage:'url(' + image + ')'});
			}
			
			var href = 'https://www.youtube.com/watch?v=' + id;
			$(this).find('a').attr({ href: href, target: '_blank'});
		});
		
		return this;
	};
	
	$.fn.showWhenScrolled = function(){
		var self = this;
		this.init = function(){
			self.each(function(){
				var frame = $(this).find('iframe');
				if($(this).isInViewport()){
					if(!frame.attr('src')){
						frame.attr({ src : frame.attr('title') });
					}
				}
			});
		};
		
		$(window).on('scroll resize orientationchange', function(){
			self.init();
		});
		
		self.init();
		
		return this;
	};

}(jQuery));