ls.print.js

/*
This lazySizes extension adds better support for print.
In case the user starts to print lazysizes will load all images.
*/
(function(window){
	/*jshint eqnull:true */
	'use strict';
	var config, elements, onprint, printMedia;
	// see also: http://tjvantoll.com/2012/06/15/detecting-print-requests-with-javascript/
	if(window.addEventListener){
		config = (window.lazySizes && lazySizes.cfg) || window.lazySizesConfig || {};
		elements = config.lazyClass || 'lazyload';
		onprint = function(){
			var i, len;
			if(typeof elements == 'string'){
				elements = document.getElementsByClassName(elements);
			}

			if(window.lazySizes){
				for(i = 0, len = elements.length; i < len; i++){
					lazySizes.loader.unveil(elements[i]);
				}
			}
		};

		addEventListener('beforeprint', onprint, false);

		if(!('onbeforeprint' in window) && window.matchMedia && (printMedia = matchMedia('print')) && printMedia.addListener){
			printMedia.addListener(function(){
				if(printMedia.matches){
					onprint();
				}
			});
		}
	}
})(window);