Simplify & improve detection of same-page anchors

If you were on URL that has `#foo` and clicked on link that has simply
`#` as href, pjax wouldn't recognize it as same-page anchor and would
allow xhr request to be initiated.

jquery.pjax.js

@@ -75,13 +75,8 @@ function handleClick(event, container, options) {
   if ( location.protocol !== link.protocol || location.hostname !== link.hostname )
     return
 
-  // Ignore anchors on the same page
-  if (link.hash && link.href.replace(link.hash, '') ===
-       location.href.replace(location.hash, ''))
-    return
-
-  // Ignore empty anchor "foo.html#"
-  if (link.href === location.href + '#')
+  // Ignore case when a hash is being tacked on the current URL
+  if ( link.href.indexOf('#') > -1 && stripHash(link) == stripHash(location) )
     return
 
   // Ignore event with default prevented
@@ -568,6 +563,16 @@ function parseURL(url) {
   return a
 }
 
+// Internal: Return the `href` component of given URL object with the hash
+// portion removed.
+//
+// location - Location or HTMLAnchorElement
+//
+// Returns String
+function stripHash(location) {
+  return location.href.replace(/#.*/, '')
+}
+
 // Internal: Build options Object for arguments.
 //
 // For convenience the first parameter can be either the container or

test/unit/fn_pjax.js

@@ -180,13 +180,34 @@ if ($.support.pjax) {
   })
 
   asyncTest("ignores same page anchors", function() {
-    var frame = this.frame
+    var event, frame = this.frame
 
     frame.$("#main").pjax("a")
 
-    var event = frame.$.Event('click')
+    event = frame.$.Event('click')
     frame.$("a[href='#main']").trigger(event)
-    notEqual(event.result, false)
+    equal(event.isDefaultPrevented(), false)
+
+    event = frame.$.Event('click')
+    frame.$("a[href='#']").trigger(event)
+    equal(event.isDefaultPrevented(), false)
+
+    start()
+  })
+
+  asyncTest("ignores same page anchors from URL that has hash", function() {
+    var event, frame = this.frame
+
+    frame.window.location = "#foo"
+    frame.$("#main").pjax("a")
+
+    event = frame.$.Event('click')
+    frame.$("a[href='#main']").trigger(event)
+    equal(event.isDefaultPrevented(), false)
+
+    event = frame.$.Event('click')
+    frame.$("a[href='#']").trigger(event)
+    equal(event.isDefaultPrevented(), false)
 
     start()
   })

test/views/home.erb

@@ -6,6 +6,7 @@
   <li><a href="/aliens.html">aliens</a></li>
   <li><a href="https://www.google.com/">Google</a></li>
   <li><a href="#main">Main</a></li>
+  <li><a href="#">Empty</a></li>
 </ul>
 
 <form action="env.html" method="GET">