Bug Report

[William Haynes]

Hi Christian,

We are just starting the Spring term, and I am using this exam as a homework assignment, https://numbas.mathcentre.ac.uk/exam/14900/01-trigonometry-review/ .

Today I got an error report from a student with the attached screenshots.

81 students have attempted the assignment, and I went through them one by one in the Numbas LTI provider clicking on 'review' for each one.  Nearly all of them were fine, but for six students, including the one who reported the error, clicking 'review' gave me this error:

It probably has something to do with the way I am loading the geogebra applet in the second and third questions, but I am at a loss to what I might be doing wrong, and why it only affects a couple of students.

Any ideas?

Thanks,

Will

[William Haynes]

Hi Christian,

After thinking this over for a couple of days, I know what is causing the problem.

My intention is for the geogebra applet to show some additional information when the student clicks on advice, so in the preamble I have this:

question.signals.on('adviceDisplayed',function() {

   var app = Numbas.exam.currentQuestion.applet.app;

   app.setValue("show",true);

   app.setVisible("show",true);

 })

 

question.applet is a variable I saved when I created the geogebra applet with a javascript function. I was doing it this way to get a reference to the applet and to work around the problems with suspend/resume  Issue 733 and discussed here.

I have temporarily turned off the adviceDisplayed stuff in the preamble, so the exam is working, but I would love an example of how to accomplish this "the right way."

Thanks,

Will