What are "scriptlets" the referred to in Windows Group Policy Editor?

The Local Group Policy Editor in Windows 7 has a policy option to restrict the running of "scriptlets". This option can be found in Computer Configuration > All Settings > Allow scriptlets and looks as shown in below image.

Presumably scriptlets are files containing some kind of programming code, but I have some questions I would like to ask:

The policy says that it is supported on "At least Inteet Explorer 7.0.".

1. Does blocking scriptlets have an effect on the JavaScript executed in the browser when visiting websites?
2. Or are these scriptlets some code running purely locally?
3. What programming language(s) are supported for these scriptlets?