I think jason_m was simply trying to encourage you to learn. Like the old saying: Give a man a fish and he will eat for a day. Teach a man to fish and he will eat for a lifetime. In other words, it's often more beneficial for you to learn how something works than to simply give you something that does exactly what you need.
In this particular case, he gave you a hint (window.location). key_s contains the key that was pressed. So, if the key is 'n', you would do: windows.location = http://example.com/next.html;
potential, no. i definitely knew the answer (Fotiman gave the solution). in my experience, many coding issues (conditional on a generally okay [not even strong] base knowledge) is mostly an issue of not knowing what keyword to search on. i gave you a window into this.
unless you can construct conditionals, loops and other minor tricks you are pretty much out at sea. if i code it for you (which i could have, but chose not to) you don't learn anything and you possibly lose out on becoming an able coder.
in all honesty, when i answered your question (keypress) i googled then implemented in a sample page for you before posting my response. i put in a fair amount of effort to validate my answer to you. thought maybe you could put in that last step.