Enhance exam navigation by adding a skip button for non-saving question transitions and implementing unsaved changes confirmation.

physics/templates/physics/partials/exam_take_fragment.html

@@ -61,6 +61,12 @@
 
             {% if next %}
                     <button type="submit" name="next" class="save btn btn-secondary" title="Click to save your answer(s) and go to the next question">Next</button>
+                    <!-- Skip: load the next question fragment without submitting the form -->
+                    <button type="button" id="skip-button" class="btn btn-outline-secondary ms-2" title="Skip to next question without saving" 
+                        hx-get="{% if cid %}{% url 'physics:exam_take_fragment' pk=exam.pk sk=pos|add:1 cid=cid passcode=passcode %}{% else %}{% url 'physics:exam_take_fragment_user' pk=exam.pk sk=pos|add:1 %}{% endif %}"
+                        hx-target="#question-fragment" hx-swap="innerHTML">Skip</button>
+                    <!-- Fallback link for non-HTMX clients: simple navigation without saving -->
+                    <a class="d-none" href="{% if cid %}{% url 'physics:exam_take' pk=exam.pk sk=pos|add:1 cid=cid passcode=passcode %}{% else %}{% url 'physics:exam_take_user' pk=exam.pk sk=pos|add:1 %}{% endif %}"></a>
             {% else %}
                 {% if not exam.publish_results %}
                     <button type="submit" name="save" class="save btn btn-default" title="Click to save your current answer(s)">Save</button>
@@ -128,6 +134,58 @@
                 document.getElementById('goto-button').value = e.currentTarget.dataset.qn;
                 $('#goto-button').click();
             });
+
+            // Skip confirmation: if the user's current selections differ from
+            // the saved answer, prompt before allowing the HTMX skip to proceed.
+            (function(){
+                const skip = document.getElementById('skip-button');
+                if(!skip) return;
+
+                // Build a JS array of saved answers (booleans) or null
+                {% if saved_answer %}
+                    const savedAnswers = [{% for s in saved_answer %}{{ s|yesno:"true,false" }}{% if not forloop.last %}, {% endif %}{% endfor %}];
+                {% else %}
+                    const savedAnswers = null;
+                {% endif %}
+
+                function readCurrent(){
+                    const lis = document.querySelectorAll('ol.physics-answer-list li');
+                    return Array.from(lis).map(li => {
+                        const inp = li.querySelector('input');
+                        return !!(inp && inp.checked);
+                    });
+                }
+
+                skip.addEventListener('click', function(evt){
+                    try{
+                        const current = readCurrent();
+                        let changed = false;
+                        if(savedAnswers === null){
+                            // no previously-saved answer; any current selection is a change
+                            changed = current.some(Boolean);
+                        } else {
+                            if(current.length === savedAnswers.length){
+                                for(let i=0;i<current.length;i++){
+                                    if(!!current[i] !== !!savedAnswers[i]){ changed = true; break; }
+                                }
+                            } else {
+                                // differing lengths — consider changed if any selection present
+                                changed = current.some(Boolean);
+                            }
+                        }
+
+                        if(changed){
+                            const ok = confirm('You have unsaved changes. Skip to the next question without saving?');
+                            if(!ok){
+                                // prevent HTMX from handling the click
+                                evt.preventDefault(); evt.stopImmediatePropagation();
+                                return false;
+                            }
+                        }
+                        // allow the HTMX attribute on the button to proceed
+                    }catch(e){ console && console.error && console.error(e); }
+                });
+            })();
         })();
     </script>
 </div>