[LON-CAPA-users] Disabling remote browser caching answers?

Stuart Raeburn raeburn at msu.edu
Fri Nov 7 16:45:54 EST 2014


Hi Ray,

> We found that, unless we disabled history on those browsers, when   
> students started to enter a numerical answer, the entire history of   
> previous submissions by other students popped to view.  Kind of   
> "gave the game away".

Thanks for the clarification; so this is an autocompletion issue.
Using an autocomplete="off" attribute for the <input> tag would address this.

Stuart Raeburn
LON-CAPA Academic Consortium


Quoting Raymond Batchelor <batchelo at sfu.ca>:

> Hi Stuart,
>
> To clarify.
> The issue is/was this:
>
> Students in a lab, use the same computers (sharing the same Windows   
> account and FireFox browser) to submit answers to a few questions,   
> before they leave.
> We found that, unless we disabled history on those browsers, when   
> students started to enter a numerical answer, the entire history of   
> previous submissions by other students popped to view.  Kind of   
> "gave the game away".
> We have disabled history in those browsers for which it was   
> previously enabled, and thus resolved that particular localized issue.
>
> Though, it would be nice to be able to selectively block history,   
> for specific response fields (I suppose), in some instances.
>
>
> Thanks,
> Ray
>
>
>
>
> ----- Original Message -----
> From: "Stuart Raeburn" <raeburn at msu.edu>
> To: lon-capa-users at mail.lon-capa.org
> Sent: Friday, 7 November, 2014 12:23:13
> Subject: Re: [LON-CAPA-users] Disabling remote browser caching answers?
>
> Hi Ray,
>
>>   What, if any, is the best way for an author or course coordinator
>> to prevent students' browsers caching answers in a problem?
>
> I doubt this is a caching issue.
>
> When rendering a problem the response header sent to the browser by
> LON-CAPA includes:
>
> Pragma: no-cache
> Cache-Control: no-cache
> Expires: <current date/time>
>
> However, if the problem is being displayed after a student has made
> prior submissions, and the status is CAN_ANSWER then the most recent
> submission will be displayed in the textbox where the student enters
> an answer.
>
> Some possibilities which could be implemented currently:
>
> (a) Set the question type for the problem to "New Randomization Each N
> Tries (default N=1)"
>
> or
>
> (b) Add a javascript function to be called on page load to set the
> value attribute for all <input> form elements with name or id
> beginning with the string: HWVAL_ to ''.
>
> Other possibilities, which would require modifications to LON-CAPA,
> would be to optionally exclude $oldresponse from the value attribute
> on the server side when the content is being rendered, and also to add
> a javascript function, as outlined in (b), to LON-CAPA itself, and
> then provide a parameter, settable by the CC, to determine whether to
> exclude $oldresponse and also run the javascript function on page load.
>
>
> Stuart Raeburn
> LON-CAPA Academic Consortium
>
>
> Quoting Raymond Batchelor <batchelo at sfu.ca>:
>
>> Hi All,
>>   What, if any, is the best way for an author or course coordinator
>> to prevent students' browsers caching answers in a problem?
>>
>> --
>> Ray
>> _______________________________________________
>> LON-CAPA-users mailing list
>> LON-CAPA-users at mail.lon-capa.org
>> http://mail.lon-capa.org/mailman/listinfo/lon-capa-users
>
> _______________________________________________
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> LON-CAPA-users at mail.lon-capa.org
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>
> --
> Raymond J. Batchelor, PhD.
> Department of Chemistry
> Simon Fraser University
>
> Phone: 778-782-5635
> _______________________________________________
> LON-CAPA-users mailing list
> LON-CAPA-users at mail.lon-capa.org
> http://mail.lon-capa.org/mailman/listinfo/lon-capa-users



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