Fix #12723 and simplification and optmization of defaultDisplay helper

src/css/defaultDisplay.js

@@ -4,17 +4,28 @@ define([
 ], function( jQuery ) {
 
 var iframe,
-	elemdisplay = { BODY: "block" };
+	elemdisplay = {};
 
 /**
  * Retrieve the actual display of a element
  * @param {String} name nodeName of the element
  * @param {Object} doc Document object
  */
+// Called only from within defaultDisplay
 function actualDisplay( name, doc ) {
 	var elem = jQuery( doc.createElement( name ) ).appendTo( doc.body ),
-		display = jQuery.css( elem[0], "display" );
-	elem.remove();
+
+		// getDefaultComputedStyle might be reliably used only on attached element
+		display = window.getDefaultComputedStyle ?
+
+			// Use of this method is a temporary fix (more like optmization) until something better comes along,
+			// since it was removed from specification and supported only in FF
+			window.getDefaultComputedStyle( elem[ 0 ] ).display : jQuery.css( elem[ 0 ], "display" );
+
+	// We don't have any data stored on the element,
+	// so use "detach" method as fast way to get rid of the element
+	elem.detach();
+
 	return display;
 }
 
@@ -31,15 +42,15 @@ function defaultDisplay( nodeName ) {
 
 		// If the simple way fails, read from inside an iframe
 		if ( display === "none" || !display ) {
+
 			// Use the already-created iframe if possible
-			iframe = ( iframe ||
-				jQuery("<iframe frameborder='0' width='0' height='0'/>")
-				.css( "cssText", "display:block !important" )
-			).appendTo( doc.documentElement );
+			iframe = (iframe || jQuery( "<iframe frameborder='0' width='0' height='0'/>" )).appendTo( doc.documentElement );
 
 			// Always write a new HTML skeleton so Webkit and Firefox don't choke on reuse
-			doc = ( iframe[0].contentWindow || iframe[0].contentDocument ).document;
-			doc.write("<!doctype html><html><body>");
+			doc = iframe[ 0 ].contentDocument;
+
+			// Support: IE
+			doc.write();
 			doc.close();
 
 			display = actualDisplay( nodeName, doc );

test/unit/css.js

@@ -543,21 +543,25 @@ test( "show() resolves correct default display for detached nodes", function(){
 	span.remove();
 });
 
-test("show() resolves correct default display #10227", function() {
-	expect(2);
+test("show() resolves correct default display #10227", 4, function() {
+	var html = jQuery( document.documentElement ),
+		body = jQuery( "body" );
 
-	var body = jQuery("body");
-	body.append(
-		"<p id='ddisplay'>a<style>body{display:none}</style></p>"
-	);
+	body.append( "<p class='ddisplay'>a<style>body{display:none}</style></p>" );
 
-	equal( body.css("display"), "none", "Initial display: none" );
+	equal( body.css("display"), "none", "Initial display for body element: none" );
 
 	body.show();
-	equal( body.css("display"), "block", "Correct display: block" );
+	equal( body.css("display"), "block", "Correct display for body element: block" );
+
+	body.append( "<p class='ddisplay'>a<style>html{display:none}</style></p>" );
+
+	equal( html.css("display"), "none", "Initial display for html element: none" );
+
+	html.show();
+	equal( html.css( "display" ), "block", "Correct display for html element: block" );
 
-	jQuery("#ddisplay").remove();
-	QUnit.expectJqData( body[0], "olddisplay" );
+	jQuery( ".ddisplay" ).remove();
 });
 
 test("show() resolves correct default display when iframe display:none #12904", function() {