Very simple javscript lazy loader object, you can add into your project, and load huge script file after page load
<style>
#preloader {
width:100%; height:100%; margin:0; padding:0;
background:#fff url('../images/preloader.gif') no-repeat center center;
position:absolute;
z-index:999;
text-align: center;
}
#preloader div{
top: 50%;
position: absolute;
left: 50%;
margin: 25px;
}
</style>
<script src="/static/lazyLoader.js" type="text/javascript"></script>
<script type="text/javascript">
window.onload = function() {
lazyLoader.addRequest('/static/libs/map/openlayers/OpenLayers_c.js', 920); // second parametr use when object said progress precent
lazyLoader.addRequest('/static/libs/map/OpenStreetMap.js', 4);
lazyLoader.addRequest('/static/libs/map/OL_Yandex.js', 15);
lazyLoader.addRequest("/static/libs/map/osm_proxy.js", 2);
lazyLoader.addRequest("/static/css/layer_style.js", 4);
lazyLoader.startLoad(init);
}
function init() {
console.log("page was load");
}
</script>
<div id="preloader"><div>0%</div></div>