You simply cannot do this with Indy. If the page requires JavaScript you need to use a real webbrowser or a webbrowser control in your application.
Perhaps the site has a kind of API, which can be used to speak with the server?
Otherwise you could only find out what calls go to the server and simulate them, but this is not easy, errorprone and may be forbidden.
Duplicate post here:
www.delphipraxis.net...avascript-error.html
// EDIT:
I just came across a security warning when I checked the URL mentioned in the image:
safeweb.norton.com/r...1&source=toolbar
Is this a try to get someone to visit the page without writing the link openly?!?