How do I Javascript?

I am trying to work with a how to from Kongregate and they give me this code

connect():void

kongregate.services.connect();

If I run it in as a script I get an error for connect():void (: is the issue, I underlined it but it is hard to see.

This should be calling the connect function from Kongregates API but instead I get the error and I cannot run it.