Thanks for the compliment, Rick. But I am completely stumped on this one so far.
I've updated the code, but with the same result. The data comes back correctly on Safari/Mac, Firefox/Mac, and Firefox/Win XP. But on IE7/ Win XP, data comes back undefined. $.ajax({ mode: "sync", port: "myPort", url: "/myFunction", cache: false, data: { theDataToCheck:theDataToCheck, GramsOrML: GramsOrML, UnitCount: UnitCount, UnitsOfMeasurement: UnitsOfMeasurement, LetOtherPeopleUseThisInfo:LetOtherPeopleUseThisInfo, ajax_call: 'true' }, success: function(data) { //handle data //data comes back undefined in IE7 } }); PHP: //put return data in $theData array $S = $this->json->encode($theData); echo $S; return; What could be making this happen on IE7/Win XP, but not on Firefox/Win XP?