Fix #11962. Standardize getter return values for empty sets.

src/manipulation.js

@@ -225,7 +225,7 @@ jQuery.fn.extend({
 			if ( value === undefined ) {
 				return elem.nodeType === 1 ?
 					elem.innerHTML.replace( rinlinejQuery, "" ) :
-					null;
+					undefined;
 			}
 
 			// See if we can take a shortcut and just use innerHTML

src/offset.js

@@ -14,7 +14,7 @@ jQuery.fn.offset = function( options ) {
 		doc = elem && elem.ownerDocument;
 
 	if ( !doc ) {
-		return null;
+		return;
 	}
 
 	if ( (body = doc.body) === elem ) {
@@ -103,7 +103,7 @@ jQuery.fn.extend({
 
 	position: function() {
 		if ( !this[0] ) {
-			return null;
+			return;
 		}
 
 		var elem = this[0],

test/unit/manipulation.js

@@ -1351,6 +1351,11 @@ test("html(undefined)", function() {
 	equal( jQuery("#foo").html("<i>test</i>").html(undefined).html().toLowerCase(), "<i>test</i>", ".html(undefined) is chainable (#5571)" );
 });
 
+test("html() on empty set", function() {
+	expect(1);
+	strictEqual( jQuery( ).html(), undefined, ".html() returns undefined for empty sets (#11962)" );
+});
+
 var testHtml = function(valueObj) {
 	expect(35);
 

test/unit/offset.js

@@ -9,6 +9,12 @@ module("offset", { teardown: moduleTeardown });
 	the iframe window and the "jQuery" symbol is used to access any static methods.
 */
 
+test("empty set", function() {
+	expect(2);
+	strictEqual( jQuery( ).offset(), undefined, "offset() returns undefined for empty set (#11962)" );
+	strictEqual( jQuery( ).position(), undefined, "position() returns undefined for empty set (#11962)" );
+});
+
 test("disconnected node", function() {
 	expect(2);