[jQuery] Val() and if statement? Possibly just wrong syntax

[Hinch]

I'm quite new to jQuery but forms are proving difficult for me. I'm
trying to make a dynamic select box named 'educType' allow or disallow
two other form fields depending on the selection. I'm pretty sure it
is just the 'if' statement being incorrect syntax but I can't find
examples for it.

Here is the code I have got below.

$(document).ready(function() {

function changeEd(){

 var edValues = $(this).val();

 if (edValues == "university") {
  $("#edcounty, #coluni").attr("disabled", this.value == 'no');
 }
}

$("#educType").change(changeEd);
changeEd();

});

I made it following the val() docs and some help from a previous post
(the code there is now in use elsewhere so thanks!) but this isn't
working and I give up!