Toggle the pagelist visibility via CSS to avoid a crash when the index update is done before the element exists.

Also only send the If-Modified-Since HTTP header when we have something significant to send.

css/style.css

@@ -363,7 +363,8 @@ a[href="javascript:;"] {
 }
 
 /* Index */
-:root.index-loading .board {
+:root.index-loading .board,
+:root.index-hide-pagelist .pagelist {
   display: none;
 }
 

lib/$.coffee

@@ -45,7 +45,7 @@ $.ajax = do ->
     type or= form and 'post' or 'get'
     r.open type, url, !sync
     if whenModified
-      r.setRequestHeader 'If-Modified-Since', lastModified[url] or '0'
+      r.setRequestHeader 'If-Modified-Since', lastModified[url] if url of lastModified
       $.on r, 'load', -> lastModified[url] = r.getResponseHeader 'Last-Modified'
     $.extend r, options
     $.extend r.upload, upCallbacks

src/Miscellaneous/Index.coffee

@@ -44,6 +44,7 @@ Index =
       subEntries: [modeEntry, sortEntry]
 
     $.addClass doc, 'index-loading'
+    Index.togglePagelist()
     Index.root = $.el 'div', className: 'board'
     Index.update()
     $.asap (-> $('.board', doc) or d.readyState isnt 'loading'), ->
@@ -52,11 +53,15 @@ Index =
 
   cb:
     mode: ->
+      Index.togglePagelist()
       Index.buildIndex()
     sort: ->
       Index.sort()
       Index.buildIndex()
 
+  togglePagelist: ->
+    (if Conf['Index Mode'] is 'paged' then $.rmClass else $.addClass) doc, 'index-hide-pagelist'
+
   update: ->
     return unless navigator.onLine
     Index.req?.abort()
@@ -170,4 +175,3 @@ Index =
     $.event 'IndexRefresh'
     $.rmAll Index.root
     $.add Index.root, nodes
-    $('.pagelist').hidden = Conf['Index Mode'] isnt 'paged'