Allow to change context in a pjax:beforeReplace handler

jquery.pjax.js

@@ -281,14 +281,14 @@ function pjax(options) {
       state: pjax.state,
       previousState: previousState
     })
-    context.html(container.contents)
+    options.context.html(container.contents)
 
     // FF bug: Won't autofocus fields that are inserted via JS.
     // This behavior is incorrect. So if theres no current focus, autofocus
     // the last field.
     //
     // http://www.w3.org/html/wg/drafts/html/master/forms.html
-    var autofocusEl = context.find('input[autofocus], textarea[autofocus]').last()[0]
+    var autofocusEl = options.context.find('input[autofocus], textarea[autofocus]').last()[0]
     if (autofocusEl && document.activeElement !== autofocusEl) {
       autofocusEl.focus();
     }

test/unit/pjax.js

@@ -563,6 +563,29 @@ if ($.support.pjax) {
     })
   })
 
+  asyncTest("change context node in pjax:beforeReplace event handler", function() {
+    var frame = this.frame,
+        targetContent = 'foo',
+        changedTarget = frame.$('ul > li:first')
+        changedTargetOriginalContent = changedTarget.text()
+
+    frame.$("#main")
+         .text(targetContent)
+         .on("pjax:beforeReplace", function(event, contents, options) {
+      options.context = changedTarget;
+    })
+    frame.$("#main").on("pjax:success", function(event) {
+      notEqual(changedTarget.text(), changedTargetOriginalContent)
+      equal($(event.target).text(), targetContent)
+      start()
+    })
+
+    frame.$.pjax({
+      url: "hello.html",
+      container: "#main"
+    })
+  })
+
   asyncTest("triggers pjax:success event from container", function() {
     var frame = this.frame