When you submit a web form, the form data sent by the browser will include the names of any input items where type="text", regardless of whether anything has been typed in the textbox.

Conversely, if the web form includes a radio button group, the form data sent by the browser will only include the (common) name of the radio buttons in the group, if one of the buttons has been selected. If it so happened that value="" for the selected radio button, then the form data would also include a a value of "" for that named element.

If none of the buttons in a radio button group has been selected, then the name of that group will not be included in the form data sent by the browser.

So, yes, the browser treats radio buttons differently from textboxes, such that in any submission you'll always see these three items:


in the "POST" item in the activity log created by a submission, because all are textboxes (input type="text"), but you'll only see this item:


if one of the radio buttons had been selected. And consequently you'll never see: HWVAL_14 = (with the right side blank), because all of the radio buttons have an associated value in this case where the radio buttons are present because it is a numericalresponse item with question type set to exam.

Stuart Raeburn
LON-CAPA Academic Consortium

Quoting Bob Gonzales <>:


Thanks for the detailed response!

I'm still confused about the line containing HWVAL_14 only showing up in a
POST  when there was a radio button selected but not at other times.  The
lines containing the other HWVAL_'s appear in every POST even when they
didn't have a value entered, and after they had values submitted.  So, from
your response, this resulted  because part 13 (HWVAL_14) was set to type
exam.  In fact, it was set to type exam.  If this is the reason, why are
exam questions  treated differently than the other questions?

Bob Gonzales

On Fri, Oct 14, 2016 at 6:16 PM, Stuart Raeburn <> wrote:


I am assuming the question type was set to "exam" for part 13, because
is a four part problem containing four numericalresponse items (one for
each part).

The "POST" entries record the value(s) entered by the student in the web
form when a submit button was pushed -- either typed into a textbox in
numericalresponse in standard mode, or the value for a radio button which
is selected, (i.e., for numericalresponse in exam mode).

However, in a multi-part problem, each part has its own "Submit Answer"
button, and the only value(s) which will be stored (in the "CSTORE") is/are
for the response item(s) belonging to the part for which the "Submit
Answer" button was pushed.

The activity log shows the following actions:

20:16:47 Submit Answer button pushed for part 11
Value for response item in part 11 (id=12) was: .0045 M

20:21:01 Submit Answer button pushed for part 15
Value for response item in part 15  (id=16) was: 26.56 g

20:23:46 Submit Answer button pushed for part 17
Value for response item in part 17 (id=18) was .282 L

The button was never pushed for part 13, so no submission is recorded for
response item 14.

However, the radio button for response item 14 (in part 13) was checked
when the button was pushed for part 15 at 20:21:01, so the POST includes a
value for "0.593069306930693" for HWVAL_14, but the submission is not
recorded in the student's submission history, because the "Submit Answer"
button was not pushed for part 13.

Stuart Raeburn
LON-CAPA Academic Consortium

Quoting Bob Gonzales <>:


I had a student who claims he submitted an answer and didn't get credit
it.  This happened during a quiz so he didn't get the problem status, or a
receipt, at the time of the submission.  In looking through the activity
file I see something that I don't understand and was wondering if it was
somehow related.

The problem has 4 parts.  The 2nd part is a radiobuttonresponse and it is
the one that the student claims to have answered.  In the activity log
excerpt below, the 2nd part is HWVAL_14.

The thing that I don't understand is that HWVAL_14 doesn't show up in the
POST on line 469 for the 1st part like the other parts do.  Then it shows
up on line 468 with a value.  Line 468 is a POST for the 3rd part as
indicated by the submission in the CSTORE on line 467.  Then on line 465,
the POST for the 4th part, HWVAL_14 is missing again.

Looking at the issue of not getting credit for the submission, did he
on a radio button but not the submit button for that part (the 2nd part).
Then when he submitted his answer for the 3rd part, the 2nd part POST'ed
too but lon-capa didn't grade it since the submit was not for the 3rd
part.  That seems reasonable.

Is there an explanation for the line HWVAL_14 appearing and disappearing?
I thought maybe the activity log might be corrupt but grading
indicates "Nothing
submitted - no attempts."

Are these 2 things related?


465     Question 2  2016-10-06 20:23:46  POST
HWVAL_12 = .0045 M
HWVAL_16 = 26.56 g
HWVAL_18 = .282 L
submitted = part_17
symb = uploaded/binghamton/7i6759115966957b9binghamtonl1/default_
466    Question 2  2016-10-06 20:23:46  CSTORE
host = binghamtona2
resource.17.18.answername = INTERNAL
resource.17.18.awarddetail = APPROX_ANS
resource.17.18.awardmsg =
resource.17.18.submission = .282 L
resource.17.award = APPROX_ANS
resource.17.awarded = 1
resource.17.awardmsg =
resource.17.duedate = 1475803800
resource.17.hinttries = 1
resource.17.maxtries = 3
resource.17.rndseed = 644052659:1049734531
resource.17.solved = correct_by_student
resource.17.tries = 1
resource.17.type = problem
resource.17.version =

467    Question 2  2016-10-06 20:21:05  CSTORE
host = binghamtona2
resource.15.16.answername = INTERNAL
resource.15.16.awarddetail = APPROX_ANS
resource.15.16.awardmsg =
resource.15.16.submission = 26.56 g
resource.15.award = APPROX_ANS
resource.15.awarded = 1
resource.15.awardmsg =
resource.15.duedate = 1475803800
resource.15.hinttries = 1
resource.15.maxtries = 3
resource.15.rndseed = 644052659:1049734531
resource.15.solved = correct_by_student
resource.15.tries = 1
resource.15.type = problem
resource.15.version =

468 Question 2  2016-10-06 20:21:01  POST
HWVAL_12 = .0045 M
HWVAL_14 = 0.593069306930693
HWVAL_16 = 26.56 g
HWVAL_18 =
submitted = part_15
symb = uploaded/binghamton/7i6759115966957b9binghamtonl1/default_
469  Question 2  2016-10-06 20:16:47  POST
HWVAL_12 = .0045 M
HWVAL_16 =
HWVAL_18 =
submitted = part_11
symb = uploaded/binghamton/7i6759115966957b9binghamtonl1/default_
470 Question 2   2016-10-06 20:16:47  CSTORE
host = binghamtona2
resource.11.12.answername = INTERNAL
resource.11.12.awarddetail = APPROX_ANS
resource.11.12.awardmsg =
resource.11.12.submission = .0045 M
resource.11.award = APPROX_ANS
resource.11.awarded = 1
resource.11.awardmsg =
resource.11.duedate = 1475803800
resource.11.hinttries = 1
resource.11.maxtries = 3
resource.11.rndseed = 644052659:1049734531
resource.11.solved = correct_by_student
resource.11.tries = 1
resource.11.type = problem
resource.11.version =

471    Question 2  2016-10-06 20:15:10   POST

Bob Gonzales

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