Support: Simplify the box-sizing test

Don't require body in the support.boxSizing test.

src/css.js

@@ -171,7 +171,7 @@ function getWidthOrHeight( elem, name, extra ) {
 	var valueIsBorderBox = true,
 		val = name === "width" ? elem.offsetWidth : elem.offsetHeight,
 		styles = getStyles( elem ),
-		isBorderBox = support.boxSizing() && jQuery.css( elem, "boxSizing", false, styles ) === "border-box";
+		isBorderBox = support.boxSizing && jQuery.css( elem, "boxSizing", false, styles ) === "border-box";
 
 	// some non-html elements return undefined for offsetWidth, so check for null/undefined
 	// svg - https://bugzilla.mozilla.org/show_bug.cgi?id=649285
@@ -366,7 +366,7 @@ jQuery.each([ "height", "width" ], function( i, name ) {
 					elem,
 					name,
 					extra,
-					support.boxSizing() && jQuery.css( elem, "boxSizing", false, styles ) === "border-box",
+					support.boxSizing && jQuery.css( elem, "boxSizing", false, styles ) === "border-box",
 					styles
 				) : 0
 			);

src/css/support.js

@@ -5,7 +5,7 @@ define([
 
 (function() {
 	// Minified: var b,c,d,e,f,g, h,i
-	var div, style, a, pixelPositionVal, boxSizingVal, boxSizingReliableVal,
+	var div, style, a, pixelPositionVal, boxSizingReliableVal,
 		reliableHiddenOffsetsVal, reliableMarginRightVal;
 
 	// Setup
@@ -33,6 +33,11 @@ define([
 	div.cloneNode( true ).style.backgroundClip = "";
 	support.clearCloneStyle = div.style.backgroundClip === "content-box";
 
+	// Support: Firefox<29, Android 2.3
+	// Vendor-prefix box-sizing
+	support.boxSizing = style.boxSizing === "" || style.MozBoxSizing === "" ||
+		style.WebkitBoxSizing === "";
+
 	jQuery.extend(support, {
 		reliableHiddenOffsets: function() {
 			if ( reliableHiddenOffsetsVal == null ) {
@@ -41,13 +46,6 @@ define([
 			return reliableHiddenOffsetsVal;
 		},
 
-		boxSizing: function() {
-			if ( boxSizingVal == null ) {
-				computeStyleTests();
-			}
-			return boxSizingVal;
-		},
-
 		boxSizingReliable: function() {
 			if ( boxSizingReliableVal == null ) {
 				computeStyleTests();
@@ -94,12 +92,6 @@ define([
 			"box-sizing:border-box;display:block;margin-top:1%;top:1%;" +
 			"border:1px;padding:1px;width:4px;position:absolute";
 
-		// Workaround failing boxSizing test due to offsetWidth returning wrong value
-		// with some non-1 values of body zoom, ticket #13543
-		jQuery.swap( body, body.style.zoom != null ? { zoom: 1 } : {}, function() {
-			boxSizingVal = div.offsetWidth === 4;
-		});
-
 		// Support: IE<9
 		// Assume reasonable values in the absence of getComputedStyle
 		pixelPositionVal = false;

test/data/support/boxSizing.html

-<!DOCTYPE html>
-<html>
-<head>
-	<meta charset="utf-8">
-	<style>
-		body {
-			zoom: 0.87;
-		}
-	</style>
-</head>
-<body>
-<script src="../../jquery.js"></script>
-<script>
-	jQuery(function() {
-		window.parent.iframeCallback( jQuery.support.boxSizing() );
-	});
-</script>
-</body>
-</html>

test/unit/support.js

@@ -45,11 +45,6 @@ if ( jQuery.css ) {
 	});
 }
 
-testIframeWithCallback( "A non-1 zoom on body doesn't cause WebKit to fail box-sizing test", "support/boxSizing.html", function( boxSizing ) {
-	expect( 1 );
-	equal( boxSizing, computedSupport.boxSizing, "box-sizing properly detected on page with non-1 body zoom" );
-});
-
 testIframeWithCallback( "A background on the testElement does not cause IE8 to crash (#9823)", "support/testElementCrash.html", function() {
 	expect( 1 );
 	ok( true, "IE8 does not crash" );