Add margin after checking width. Add tests. Fixes #9441. Fixes #9300.

src/css.js

@@ -168,12 +168,11 @@ jQuery.curCSS = jQuery.css;
 jQuery.each(["height", "width"], function( i, name ) {
 	jQuery.cssHooks[ name ] = {
 		get: function( elem, computed, extra ) {
-			var val;
+			var val, fellback = false;
 
 			if ( computed ) {
 				if ( elem.offsetWidth !== 0 ) {
 					val = getWH( elem, name, extra );
-
 				} else {
 					jQuery.swap( elem, cssShow, function() {
 						val = getWH( elem, name, extra );
@@ -188,20 +187,37 @@ jQuery.each(["height", "width"], function( i, name ) {
 					}
 
 					if ( val != null ) {
-						// Should return "auto" instead of 0, use 0 for
-						// temporary backwards-compat
-						return val === "" || val === "auto" ? "0px" : val;
+						fellback = true;
 					}
 				}
 
-				if ( val < 0 || val == null ) {
+				if ( !fellback && ( val < 0 || val == null ) ) {
 					val = elem.style[ name ];
+					fellback = true;
+				}
+
 				// Should return "auto" instead of 0, use 0 for
 				// temporary backwards-compat
-					return val === "" || val === "auto" ? "0px" : val;
+				if ( fellback && ( val === "" || val === "auto" ) ) {
+					val = "0px";
+				} else if ( typeof val !== "string" ) {
+					val += "px";
+				}
+
+				if ( extra ) {
+					val = parseFloat( val ) || 0;
+					if ( fellback ) {
+						val += adjustWH( elem, name, "padding" );
+						if ( extra !== "padding" ) {
+							val += adjustWH( elem, name, "border", "Width" );
+						}
+					}
+					if ( extra === "margin" ) {
+						val += adjustWH( elem, name, "margin" );
+					}
 				}
 
-				return typeof val === "string" ? val : val + "px";
+				return val;
 			}
 		},
 
@@ -331,24 +347,33 @@ if ( document.documentElement.currentStyle ) {
 curCSS = getComputedStyle || currentStyle;
 
 function getWH( elem, name, extra ) {
-	var which = name === "width" ? cssWidth : cssHeight,
-		val = name === "width" ? elem.offsetWidth : elem.offsetHeight;
+	var val = name === "width" ? elem.offsetWidth : elem.offsetHeight;
 
 	if ( extra === "border" ) {
 		return val;
 	}
 
-	jQuery.each( which, function() {
 	if ( !extra ) {
-			val -= parseFloat(jQuery.css( elem, "padding" + this )) || 0;
+		val -= adjustWH( elem, name, "padding");
 	}
 
-		if ( extra === "margin" ) {
-			val += parseFloat(jQuery.css( elem, "margin" + this )) || 0;
+	if ( extra !== "margin" ) {
+		val -= adjustWH( elem, name, "border", "Width");
+	}
 
-		} else {
-			val -= parseFloat(jQuery.css( elem, "border" + this + "Width" )) || 0;
+	return val;
+}
+
+function adjustWH( elem, name, prepend, append ) {
+	var which = name === "width" ? cssWidth : cssHeight,
+		val = 0;
+
+	if( !append ){
+		append = "";
 	}
+
+	jQuery.each( which, function() {
+		val += parseFloat( jQuery.css( elem, prepend + this + append ) ) || 0;
 	});
 
 	return val;

test/unit/dimensions.js

@@ -211,6 +211,30 @@ test("outerWidth()", function() {
 	jQuery.removeData($div[0], "olddisplay", true);
 });
 
+test("child of a hidden elem has accurate inner/outer/Width()/Height()  see #9441 #9300", function() {
+	expect(8);
+
+	//setup html
+	var $divNormal = jQuery( '<div>' ).css({ width: "100px", border: "10px solid white", padding: "2px", margin: "3px" });
+	var $divChild = $divNormal.clone();
+	var $divHiddenParent = jQuery( '<div>' ).css( "display", "none" ).append( $divChild );
+	jQuery( 'body' ).append( $divHiddenParent ).append( $divNormal );
+
+	//tests that child div of a hidden div works the same as a normal div
+	equals( $divChild.width(), $divNormal.width(), "child of a hidden element width() is wrong see #9441" );
+	equals( $divChild.innerWidth(), $divNormal.innerWidth(), "child of a hidden element innerWidth() is wrong see #9441" );
+	equals( $divChild.outerWidth(), $divNormal.outerWidth(), "child of a hidden element outerWidth() is wrong see #9441" );
+	equals( $divChild.outerWidth(true), $divNormal.outerWidth( true ), "child of a hidden element outerWidth( true ) is wrong see #9300" );
+	equals( $divChild.height(), $divNormal.height(), "child of a hidden element height() is wrong see #9441" );
+	equals( $divChild.innerHeight(), $divNormal.innerHeight(), "child of a hidden element innerHeight() is wrong see #9441" );
+	equals( $divChild.outerHeight(), $divNormal.outerHeight(), "child of a hidden element outerHeight() is wrong see #9441" );
+	equals( $divChild.outerHeight(true), $divNormal.outerHeight( true ), "child of a hidden element outerHeight( true ) is wrong see #9300" );
+
+	//teardown html
+	$divHiddenParent.remove();
+	$divNormal.remove();
+});
+
 test("outerHeight()", function() {
 	expect(11);