That's called load. It came waaaaay before DOM ready was around, and DOM ready was actually created for the exact reason that load waited on images.
window.addEventListener('load', function () { alert("It's loaded!") })
<script src="js/jquery-1.11.0.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(document).ready(function () {
yourFunction();
});
function yourFunction(){
//some code
}
</script>