limit exam duration to 99999 minutes, fixes #201

views/sheets/edit_assignment.php

@@ -58,7 +58,7 @@
 
         <label id="exam_length" class="practice-hidden selftest-hidden">
             <span class="required"><?= _vips('Dauer in Minuten') ?></span>
-            <input type="number" name="exam_length" value="<?= htmlReady($assignment->options['duration']) ?>" <?= $disabled ?> data-secure required>
+            <input type="number" name="exam_length" min="0" max="99999" value="<?= htmlReady($assignment->options['duration']) ?>" <?= $disabled ?> data-secure required>
         </label>
 
         <input id="options-toggle" type="checkbox" value="on" <?= $assignment_id ? '' : 'checked' ?>>