Left / right arrow keys to switch pages in problem set

views/page.ejs

@@ -1,7 +1,7 @@
 <% if (paginate.pageCnt) { %>
 <div class="ui center aligned grid">
     <div class="ui buttons">
-        <a class="ui<% if (paginate.currPage === 1) { %> disabled<% } %> button" href="<%= syzoj.utils.makeUrl(req, Object.assign(req.query, { page: paginate.currPage - 1 })) %>">
+        <a class="ui<% if (paginate.currPage === 1) { %> disabled<% } %> button" <% if (paginate.currPage !== 1) { %>href="<%= syzoj.utils.makeUrl(req, Object.assign(req.query, { page: paginate.currPage - 1 })) %>" <% } %>id="page_prev">
             <i class="left chevron icon"></i>
         </a>
         <%
@@ -27,7 +27,7 @@
         %>
         <li><span>...</span></li>
         <% } %>
-        <a class="ui<% if (paginate.currPage === paginate.pageCnt) { %> disabled<% } %> button" href="<%= syzoj.utils.makeUrl(req, Object.assign(req.query, { page: paginate.currPage + 1 })) %>">
+        <a class="ui<% if (paginate.currPage === paginate.pageCnt) { %> disabled<% } %> button" <% if (paginate.currPage !== paginate.pageCnt) { %>href="<%= syzoj.utils.makeUrl(req, Object.assign(req.query, { page: paginate.currPage + 1 })) %>" <% } %>id="page_next">
             <i class="right chevron icon"></i>
         </a>
     </div>

views/problem_set.ejs

@@ -49,5 +49,11 @@
     </tbody>
   </table><br>
   <% include page  %>
+<script>
+document.addEventListener('keydown', function (event) {
+  if (event.keyCode === 39) document.getElementById('page_next').click();
+  else if (event.keyCode === 37) document.getElementById('page_prev').click();
+});
+</script>
 </div>
 <% include footer %>