Move XHR abort code into a function.

Author: AlexHill

jquery.pjax.js

@@ -339,11 +339,7 @@ function pjax(options) {
   }
 
   // Cancel the current request if we're already pjaxing
-  var xhr = pjax.xhr
-  if ( xhr && xhr.readyState < 4) {
-    xhr.onreadystatechange = $.noop
-    xhr.abort()
-  }
+  abortXHR(pjax.xhr)
 
   pjax.options = options
   var xhr = pjax.xhr = $.ajax(options)
@@ -409,12 +405,8 @@ if ('state' in window.history) {
 // stuff yet.
 function onPjaxPopstate(event) {
 
-  // Cancel the current request if we're already pjaxing
-  var xhr = pjax.xhr
-  if ( xhr && xhr.readyState < 4) {
-    xhr.onreadystatechange = $.noop
-    xhr.abort()
-  }
+  // hitting back or forward should override any pending PJAX request
+  abortXHR(pjax.xhr);
 
   var state = event.state
 
@@ -518,6 +510,16 @@ function fallbackPjax(options) {
   form.submit()
 }
 
+
+// Internal: Abort an XmlHttpRequest if it hasn't been completed,
+// also removing its event handlers.
+function abortXHR(xhr) {
+  if ( xhr && xhr.readyState < 4) {
+    xhr.onreadystatechange = $.noop
+    xhr.abort()
+  }
+}
+
 // Internal: Generate unique id for state object.
 //
 // Use a timestamp instead of a counter since ids should still be