From fbf829b7245f7d76ea02a44ab0a62427214b7575 Mon Sep 17 00:00:00 2001
From: Timmy Willison <timmywillisn@gmail.com>
Date: Mon, 30 Nov 2015 11:30:31 -0500
Subject: [PATCH] Attributes: exclusively lowercase A-Z in attribute names

Fixes gh-2730
Close gh-2749
---
 src/attributes/attr.js  | 11 +++++++++--
 test/unit/attributes.js | 13 ++++++++++++-
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/attributes/attr.js b/src/attributes/attr.js
index ae48676d1..00b08489d 100644
--- a/src/attributes/attr.js
+++ b/src/attributes/attr.js
@@ -7,7 +7,14 @@ define( [
 ], function( jQuery, access, support, rnotwhite ) {
 
 var boolHook,
-	attrHandle = jQuery.expr.attrHandle;
+	attrHandle = jQuery.expr.attrHandle,
+
+	// Exclusively lowercase A-Z in attribute names (gh-2730)
+	// https://dom.spec.whatwg.org/#converted-to-ascii-lowercase
+	raz = /[A-Z]+/g,
+	lowercase = function( ch ) {
+		return ch.toLowerCase();
+	};
 
 jQuery.fn.extend( {
 	attr: function( name, value ) {
@@ -39,7 +46,7 @@ jQuery.extend( {
 		// All attributes are lowercase
 		// Grab necessary hook if one is defined
 		if ( nType !== 1 || !jQuery.isXMLDoc( elem ) ) {
-			name = name.toLowerCase();
+			name = name.replace( raz, lowercase );
 			hooks = jQuery.attrHooks[ name ] ||
 				( jQuery.expr.match.bool.test( name ) ? boolHook : undefined );
 		}
diff --git a/test/unit/attributes.js b/test/unit/attributes.js
index 9bf287688..cbf83d0ec 100644
--- a/test/unit/attributes.js
+++ b/test/unit/attributes.js
@@ -451,7 +451,9 @@ QUnit.test( "attr(String, Object)", function( assert ) {
 
 	$radio = jQuery( "<input>", {
 		"value": "sup",
-		"type": "radio"
+		// Use uppercase here to ensure the type
+		// attrHook is still used
+		"TYPE": "radio"
 	} ).appendTo( "#testForm" );
 	assert.equal( $radio.val(), "sup", "Value is not reset when type is set after value on a radio" );
 
@@ -472,6 +474,15 @@ QUnit.test( "attr(String, Object)", function( assert ) {
 	assert.equal( jQuery( "#name" ).attr( "nonexisting", undefined ).attr( "nonexisting" ), undefined, ".attr('attribute', undefined) does not create attribute (#5571)" );
 } );
 
+QUnit.test( "attr(non-ASCII)", function( assert ) {
+	assert.expect( 2 );
+
+	var $div = jQuery( "<div Ω='omega' aØc='alpha'></div>" ).appendTo( "#qunit-fixture" );
+
+	assert.equal( $div.attr( "Ω" ), "omega", ".attr() exclusively lowercases characters in the range A-Z (gh-2730)" );
+	assert.equal( $div.attr( "AØC" ), "alpha", ".attr() exclusively lowercases characters in the range A-Z (gh-2730)" );
+} );
+
 QUnit.test( "attr - extending the boolean attrHandle", function( assert ) {
 	assert.expect( 1 );
 	var called = false,