lazyLoad от Robin Osborne

      <img src="1x1.gif" class="lazy" data-src="real-image.jpg" alt="" />
<noscript><img src="http://static5.comicvine.com/uploads/scale_super/0/1867/583739-hawkeyei.jpg" alt="" /></noscript>

    

      var lazy = [];
registerListener('load', setLazy);
registerListener('load', lazyLoad);
registerListener('scroll', lazyLoad);
registerListener('resize', lazyLoad);
function setLazy(){
    lazy = document.getElementsByClassName('lazy');
    console.log('Found ' + lazy.length + ' lazy images');
}
function lazyLoad(){
    for(var i=0; i= 0 &&
        rect.right >= 0 &&
        rect.top <= (window.innerHeight || document.documentElement.clientHeight) &&
        rect.left <= (window.innerWidth || document.documentElement.clientWidth)
     );
}
function registerListener(event, func) {
    if (window.addEventListener) {
        window.addEventListener(event, func)
    } else {
        window.attachEvent('on' + event, func)
    }
}