Here is the relevant HTML code that makes the above animation work:
<script type="text/javascript" src="jsani/jsani.loader.js"></script>
</head>
<body>
<form name="jsani" id="jsani" action="#" style="width: 700px; height: 570px;">
<input type="hidden" name="filenames" value="midwest_radar_1.gif,midwest_radar_2.gif,midwest_radar_3.gif,midwest_radar_4.gif,midwest_radar_5.gif">
<input type="hidden" name="overlay_filenames" value="
midwest_city_1.gif|midwest_city_2.gif|midwest_city_3.gif|midwest_city_4.gif|midwest_city_5.gif,
midwest_county_basemap_1.gif|midwest_county_basemap_2.gif|midwest_county_basemap_3.gif|midwest_county_basemap_4.gif|midwest_county_basemap_5.gif,
midwest_obs_1.gif|midwest_obs_2.gif|midwest_obs_3.gif|midwest_obs_4.gif|midwest_obs_5.gif">
<input type="hidden" name="overlay_labels" value="Cities/on, Counties, Wx/on">
<input type="hidden" name="transparency" value="#000000">
<input type="hidden" name="imgbaseurl" value="images">
<input type="hidden" name="controls" value="previous, stopplay, next, looprock, slowfast, zoom, refresh">
<input type="hidden" name="maxdwell" value="1000">
<input type="hidden" name="maxdwell" value="1000">
<input type="hidden" name="mindwell" value="40">
<input type="hidden" name="initdwell" value="300">
<input type="hidden" name="nsteps" value="10">
<input type="hidden" name="missingimages" value="hide">
</form>