javascript: window.onload = function() { opacity('container', 49, 50, 100, 'images/2.jpg'); opacity('container1', 49, 50, 100, 'images/1.jpg'); } function swap(opacity, id,img_src) { document[id].src=img_src; } function opacity(id, opacStart, opacEnd, millisec, img_src) { //speed for each frame...