POST statement in jquery

I can't do it at all and I'm stuck.
It seems so easy to do.

//Add the videoId, if any, to the database. $.post is a method to do HTTP POST
$.post("list",{'videoid':videoId[listIndex] },
function(json){alert("POSTed!!!!"}
);

I was thinking that I had written an insert statement in lilstAction that had two identical room_id numbers that had to be unique.