Index: wp-admin/admin-header.php
===================================================================
--- wp-admin/admin-header.php	(revision 19794)
+++ wp-admin/admin-header.php	(working copy)
@@ -55,7 +55,7 @@
 		'uid': '<?php if ( ! isset($current_user) ) $current_user = wp_get_current_user(); echo $current_user->ID; ?>',
 		'time':'<?php echo time() ?>'
 	},
-	ajaxurl = '<?php echo admin_url('admin-ajax.php'); ?>',
+	ajaxurl = '<?php echo wp_ajax_url(); ?>',
 	pagenow = '<?php echo $current_screen->id; ?>',
 	typenow = '<?php echo $current_screen->post_type; ?>',
 	adminpage = '<?php echo $admin_body_class; ?>',
Index: wp-admin/includes/image-edit.php
===================================================================
--- wp-admin/includes/image-edit.php	(revision 19794)
+++ wp-admin/includes/image-edit.php	(working copy)
@@ -67,7 +67,7 @@
 	<input type="hidden" id="imgedit-y-<?php echo $post_id; ?>" value="<?php echo $meta['height']; ?>" />
 
 	<div id="imgedit-crop-<?php echo $post_id; ?>" class="imgedit-crop-wrap">
-	<img id="image-preview-<?php echo $post_id; ?>" onload="imageEdit.imgLoaded('<?php echo $post_id; ?>')" src="<?php echo admin_url('admin-ajax.php'); ?>?action=imgedit-preview&amp;_ajax_nonce=<?php echo $nonce; ?>&amp;postid=<?php echo $post_id; ?>&amp;rand=<?php echo rand(1, 99999); ?>" />
+	<img id="image-preview-<?php echo $post_id; ?>" onload="imageEdit.imgLoaded('<?php echo $post_id; ?>')" src="<?php echo wp_ajax_url(); ?>?action=imgedit-preview&amp;_ajax_nonce=<?php echo $nonce; ?>&amp;postid=<?php echo $post_id; ?>&amp;rand=<?php echo rand(1, 99999); ?>" />
 	</div>
 
 	<div class="imgedit-submit">
Index: wp-admin/includes/media.php
===================================================================
--- wp-admin/includes/media.php	(revision 19794)
+++ wp-admin/includes/media.php	(working copy)
@@ -334,7 +334,7 @@
 //<![CDATA[
 addLoadEvent = function(func){if(typeof jQuery!="undefined")jQuery(document).ready(func);else if(typeof wpOnload!='function'){wpOnload=func;}else{var oldonload=wpOnload;wpOnload=function(){oldonload();func();}}};
 var userSettings = {'url':'<?php echo SITECOOKIEPATH; ?>','uid':'<?php if ( ! isset($current_user) ) $current_user = wp_get_current_user(); echo $current_user->ID; ?>','time':'<?php echo time(); ?>'};
-var ajaxurl = '<?php echo admin_url('admin-ajax.php'); ?>', pagenow = 'media-upload-popup', adminpage = 'media-upload-popup',
+var ajaxurl = '<?php echo wp_ajax_url(); ?>', pagenow = 'media-upload-popup', adminpage = 'media-upload-popup',
 isRtl = <?php echo (int) is_rtl(); ?>;
 //]]>
 </script>
Index: wp-admin/includes/template.php
===================================================================
--- wp-admin/includes/template.php	(revision 19794)
+++ wp-admin/includes/template.php	(working copy)
@@ -1390,7 +1390,7 @@
 		'uid': '<?php if ( ! isset($current_user) ) $current_user = wp_get_current_user(); echo $current_user->ID; ?>',
 		'time':'<?php echo time() ?>'
 	},
-	ajaxurl = '<?php echo admin_url('admin-ajax.php'); ?>',
+	ajaxurl = '<?php echo wp_ajax_url(); ?>',
 	pagenow = '<?php echo $current_screen->id; ?>',
 	typenow = '<?php echo $current_screen->post_type; ?>',
 	adminpage = '<?php echo $admin_body_class; ?>',
Index: wp-admin/press-this.php
===================================================================
--- wp-admin/press-this.php	(revision 19794)
+++ wp-admin/press-this.php	(working copy)
@@ -304,7 +304,7 @@
 //<![CDATA[
 addLoadEvent = function(func){if(typeof jQuery!="undefined")jQuery(document).ready(func);else if(typeof wpOnload!='function'){wpOnload=func;}else{var oldonload=wpOnload;wpOnload=function(){oldonload();func();}}};
 var userSettings = {'url':'<?php echo SITECOOKIEPATH; ?>','uid':'<?php if ( ! isset($current_user) ) $current_user = wp_get_current_user(); echo $current_user->ID; ?>','time':'<?php echo time() ?>'};
-var ajaxurl = '<?php echo admin_url('admin-ajax.php'); ?>', pagenow = 'press-this', isRtl = <?php echo (int) is_rtl(); ?>;
+var ajaxurl = '<?php echo wp_ajax_url(); ?>', pagenow = 'press-this', isRtl = <?php echo (int) is_rtl(); ?>;
 var photostorage = false;
 //]]>
 </script>
Index: wp-includes/class-wp-editor.php
===================================================================
--- wp-includes/class-wp-editor.php	(revision 19794)
+++ wp-includes/class-wp-editor.php	(working copy)
@@ -576,7 +576,7 @@
 		}
 
 		if ( !is_admin() )
-			echo 'var ajaxurl = "' . admin_url('admin-ajax.php') . '";';
+			echo 'var ajaxurl = "' . wp_ajax_url() . '";';
 ?>
 	</script>
 <?php
Index: wp-includes/link-template.php
===================================================================
--- wp-includes/link-template.php	(revision 19794)
+++ wp-includes/link-template.php	(working copy)
@@ -1974,6 +1974,19 @@
 }
 
 /**
+ * Retrieve the relative url to admin-ajax.php (for proper work with IDN domains).
+ *
+ * @link http://bugs.jquery.com/ticket/8419
+ * @package WordPress
+ * @since 3.4.0
+ *
+ * @return string Relative admin-ajax.php url.
+*/
+function wp_ajax_url() {
+	return preg_replace( '#^http(s)?://[^/]*#', '', get_admin_url( null, 'admin-ajax.php' ) );
+}
+
+/**
  * Retrieve the url to the includes directory.
  *
  * @package WordPress
Index: wp-includes/media.php
===================================================================
--- wp-includes/media.php	(revision 19794)
+++ wp-includes/media.php	(working copy)
@@ -1096,7 +1096,7 @@
 <script type="text/javascript">
 /* <![CDATA[ */
 	jQuery(document).ready(function($){
-		$.get("<?php echo admin_url( 'admin-ajax.php?action=oembed-cache&post=' . $post_ID ); ?>");
+		$.get("<?php echo add_query_arg( array( 'action' => 'oembed-cache', 'post' => $post_ID ), wp_ajax_url() ); ?>");
 	});
 /* ]]> */
 </script>