Fixes #9239. If the body is already present in the DOM, use a div wit…

…hin it to perform boxModel-related support tests. Unit test added.

src/support.js

@@ -13,7 +13,9 @@ jQuery.support = (function() {
 		support,
 		fragment,
 		body,
-		bodyStyle,
+		testElementParent,
+		testElement,
+		testElementStyle,
 		tds,
 		events,
 		eventName,
@@ -136,9 +138,11 @@ jQuery.support = (function() {
 	// Figure out if the W3C box model works as expected
 	div.style.width = div.style.paddingLeft = "1px";
 
-	// We use our own, invisible, body
-	body = document.createElement( "body" );
-	bodyStyle = {
+	body = document.getElementsByTagName( "body" )[ 0 ];
+	// We use our own, invisible, body unless the body is already present
+	// in which case we use a div (#9239)
+	testElement = document.createElement( body ? "div" : "body" );
+	testElementStyle = {
 		visibility: "hidden",
 		width: 0,
 		height: 0,
@@ -147,11 +151,19 @@ jQuery.support = (function() {
 		// Set background to avoid IE crashes when removing (#9028)
 		background: "none"
 	};
-	for ( i in bodyStyle ) {
-		body.style[ i ] = bodyStyle[ i ];
+	if ( body ) {
+		jQuery.extend( testElementStyle, {
+			position: "absolute",
+			left: -1000,
+			top: -1000
+		});
+	}
+	for ( i in testElementStyle ) {
+		testElement.style[ i ] = testElementStyle[ i ];
 	}
-	body.appendChild( div );
-	documentElement.insertBefore( body, documentElement.firstChild );
+	testElement.appendChild( div );
+	testElementParent = body || documentElement;
+	testElementParent.insertBefore( testElement, testElementParent.firstChild );
 
 	// Check if a disconnected checkbox will retain its checked
 	// value of true after appended to the DOM (IE6/7)
@@ -210,8 +222,8 @@ jQuery.support = (function() {
 	}
 
 	// Remove the body element we added
-	body.innerHTML = "";
-	documentElement.removeChild( body );
+	testElement.innerHTML = "";
+	testElementParent.removeChild( testElement );
 
 	// Technique from Juriy Zaytsev
 	// http://thinkweb2.com/projects/prototype/detecting-event-support-without-browser-sniffing/

test/unit/support.js

@@ -30,3 +30,26 @@ function supportIFrameTest( title, url, noDisplay, func ) {
 supportIFrameTest( "proper boxModel in compatMode CSS1Compat (IE6 and IE7)", "boxModelIE", function( compatMode, boxModel ) {
 	ok( compatMode !== "CSS1Compat" || boxModel, "boxModel properly detected" );
 });
+
+supportIFrameTest( "body background is not lost if set prior to loading jQuery (#9238)", "bodyBackground", function( color, support ) {
+	expect( 2 );
+	var okValue = {
+			"#000000": true,
+			"rgb(0, 0, 0)": true
+	};
+	ok( okValue[ color ], "color was not reset (" + color + ")" );
+	var i, passed = true;
+	for ( i in jQuery.support ) {
+		if ( jQuery.support[ i ] !== support[ i ] ) {
+			passed = false;
+			strictEquals( jQuery.support[ i ], support[ i ], "Support property " + i + " is different" );
+		}
+	}
+	for ( i in support ) {
+		if ( !( i in jQuery.support ) ) {
+			ok = false;
+			strictEquals( src[ i ], dest[ i ], "Unexpected property: " + i );
+		}
+	}
+	ok( passed, "Same support properties" );
+});