+Before an attempt may be started there are a series of mandatory and optional +checks, to determine if the user is allowed to attempt the quiz. In addition to +these checks, the page display and functionality are slightly different for +users with and without teacher privileges. Also, when the quiz is set to start +in "secure" mode (the $quiz->popup option), the printing of the page is slightly +different. Including all of these scenarios evidently complicates the structure +of the attempt.php script, deviating from the simple scenario described above. + +
+ +First of all, access to the quiz is denied to guests. Additionally it is +possible to restrict acces to an IP range ($quiz->subnet) and to set up a +password for the quiz ($quiz->password). In both cases users that can't pass the +required tests are denied access. + +
+ +When a teacher "attempts" a quiz there is a tab navigation facility at the top +of the page, which allows the teacher to jump between reviewing, previewing and +editing the quiz (and possibly even more options). The teacher interface also +contains a button to start a new attempt, which is not present on the student +interface. Teachers' attempts are automatically marked as previews, which means +that old attempts are automatically deleted when a new attempt is started. It +also prevents previews to show up in the students' answers review and preview +attempts don't block the possibility of editing the quiz, while students' +attempts do. + +
+ +Further complication is introduced by the feature to allow multiple pages with +questions and navigation between these pages. This requieres mechanisms to +determine which questions are on which page, which page is currently displayed +and which page needs to be viewed next. This is not too hard to achieve, +however, one subtlety should be noted: when the attempt is closed it is +necessary to load all questions and their most recent states before they are +marked, whereas in the case of navgation only the questions and related states +of the page that was displayed before are loaded, processed and saved; and the +questions and states for the next page are loaded. + +
+ +Towards the end of the script there are two blocks of code that are responsible +for timed quizzes ($quiz->timelimit). The first block prints the start element +of the form using javascript to make sure that javascript is enabled (which +obviously doesn't help a lot, because the quiz is printed as usual, only the +submit won't work). The second block includes the file jstimer.php, which prints +a timer that counts down and causes an auto-submit when time is up. +
- -