Follow the process to see the main effect of NLSClientScript.
1. A small data is associated now to a DOM element via jquery api:
<script> $.data(document.body, "test","I'm the Body!"); </script>
2. Let's invoke a modal dialog several times, displaying remote content. The point: jQuery will process html content, containing script tags with src.
Check in Firebug what js files are downloaded and executed while the action is being processed.
Be warned: Firebug, if opened, may freeze the page for some seconds here.
3. Check what is in jQuery's storage now.
You should see an alert with text "I'm the Body!".
NLSClientScript prevented to pull the same libraries more than once, this way it prevents unwanted re-initializations.
Now repeat the flow without NLSClientScript.