// JSON formatted record:

( {"Records": [
{"room_no":"100","room_id":"752"},
{"room_no":"102","room_id":"753"},
{"room_no":"103","room_id":"754"},
], "RecordCount":"3" } )

myRecords = eval(myJSON);

var columnName1 = "room_no";
var columnName2 = "room_id";

for(i = 0; i < myRecords.RecordCount; i++)
{
    alert(myRecords.Records[i].room_no); // This works
    alert(myRecords.Records[i].room_id); // This works
    alert(myRecords.Records[i].columnName1); // Does not work
    alert(myRecords.Records[i].columnName2); // Does not work
}

// Is it possible to address my object in such a way that I can use the value of a variable for my method name?