Merge branch 'before-replace'

Fixes #383, closes #384

Author: mislav

README.md

@@ -230,6 +230,12 @@ container, not the link that was clicked.
   <td><code>options</code></td>
   <td>fires after pjax has started from a link that got clicked</td>
 </tr>
+<tr>
+  <td><code>pjax:beforeReplace</code></td>
+  <td></td>
+  <td><code>contents, options</code></td>
+  <td>before replacing HTML with content loaded from the server</td>
+</tr>
 <tr>
   <td><code>pjax:success</code></td>
   <td></td>
@@ -275,6 +281,12 @@ container, not the link that was clicked.
   <td><code>null, options</code></td>
   <td>before replacing content</td>
 </tr>
+<tr>
+  <td><code>pjax:beforeReplace</code></td>
+  <td></td>
+  <td><code>contents, options</code></td>
+  <td>right before replacing HTML with content from cache</td>
+</tr>
 <tr>
   <td><code>pjax:end</code></td>
   <td></td>

jquery.pjax.js

@@ -272,6 +272,8 @@ function pjax(options) {
     } catch (e) { }
 
     if (container.title) document.title = container.title
+
+    fire('pjax:beforeReplace', [container.contents, options])
     context.html(container.contents)
 
     // FF bug: Won't autofocus fields that are inserted via JS.
@@ -446,6 +448,7 @@ function onPjaxPopstate(event) {
         container.trigger('pjax:start', [null, options])
 
         if (state.title) document.title = state.title
+        container.trigger('pjax:beforeReplace', [contents, options])
         container.html(contents)
         pjax.state = state
 

test/unit/pjax.js

@@ -536,6 +536,28 @@ if ($.support.pjax) {
     })
   })
 
+  asyncTest("triggers pjax:beforeReplace event from container", function() {
+    var frame = this.frame,
+        beforeContent = 'foo'
+
+    frame.$("#main")
+         .text(beforeContent)
+         .on("pjax:beforeReplace", function(event, contents, options) {
+      ok(event)
+      ok(contents)
+      equal($(event.target).text(), beforeContent)
+      equal(options.url, "hello.html")
+    })
+    frame.$("#main").on("pjax:success", function(event) {
+      notEqual($(event.target).text(), beforeContent)
+      start()
+    })
+
+    frame.$.pjax({
+      url: "hello.html",
+      container: "#main"
+    })
+  })
 
   asyncTest("triggers pjax:success event from container", function() {
     var frame = this.frame
@@ -828,6 +850,34 @@ if ($.support.pjax) {
     })
   })
 
+  asyncTest("popstate triggers pjax:beforeReplace event", function() {
+    var frame = this.frame,
+        originalContent = $(frame).html()
+
+    equal(frame.location.pathname, "/home.html")
+
+    frame.$('#main').on("pjax:complete", function() {
+      equal(frame.location.pathname, "/hello.html")
+      ok(frame.history.length > 1)
+
+      frame.$('#main').on('pjax:beforeReplace', function(event, contents, options) {
+        ok(event)
+        ok(contents)
+        equal(frame.location.pathname, "/home.html")
+        // Remember: the content hasn't yet been replaced.
+        notEqual($(event.target).html(), originalContent)
+        start()
+      })
+
+      goBack(frame, function() {})
+    })
+
+    frame.$.pjax({
+      url: "hello.html",
+      container: "#main"
+    })
+  })
+
   // Test is fragile
   asyncTest("no initial pjax:popstate event", function() {
     var frame = this.frame