Simple image LazyLoader with jQuery.isOnScreen

simple_img_lazyloader.js

var imagesBlock = jQuery('#imagesBlock');
var sliderVisible = imagesBlock.isOnScreen(0, -1); // https://github.com/moagrius/isOnScreen
if (typeof jQuery().isOnScreen === 'function' && !sliderLoaded && sliderVisible) {
	var imgs = imagesBlock.find("img");
	for(var i = 0; i < imgs.length; i++){
		var img = jQuery(imgs[i]);
		img.attr("src", img.attr("ref-src")); // replace 'ref-src' attribute with 'src'
	}
	sliderLoaded = true;
}