Scroll to named anchors after pjax navigation

Only elements with IDs were supported before. But since the browser will
natively also scroll to matching `<a name="...">` elements, we need to
support those as well.

Author: mislav

jquery.pjax.js

@@ -327,7 +327,8 @@ function pjax(options) {
       pjax.state.url = url.href
       window.history.replaceState(pjax.state, container.title, url.href)
 
-      var target = document.getElementById(url.hash.slice(1))
+      var name = hash.slice(1)
+      var target = document.getElementById(name) || document.getElementsByName(name)[0]
       if (target) $(window).scrollTop($(target).offset().top)
     }
 

test/views/anchor.erb

@@ -1,4 +1,4 @@
 <%= title 'Anchor' %>
 <div id="top" style="width:500px;height:10000px;"></div>
-<div id="bottom" style="width:500px;height:10000px;"></div>
+<a name="bottom" style="width:500px;height:10000px;display:block;"></a>
 <script type="text/javascript">window.parent.iframeLoad(window)</script>