Offset: Increase search depth when finding the 'real' offset parent

Changes:
* Increase search depth when finding for the real offset parent
* Ignore offset for statically positioned offset parent
* Add tests for the position of an element in a table

Closes gh-4861

Author: Minimaximize

src/offset.js

@@ -121,12 +121,13 @@ jQuery.fn.extend( {
 			doc = elem.ownerDocument;
 			offsetParent = elem.offsetParent || doc.documentElement;
 			while ( offsetParent &&
-				( offsetParent === doc.body || offsetParent === doc.documentElement ) &&
+				offsetParent !== doc.documentElement &&
 				jQuery.css( offsetParent, "position" ) === "static" ) {
 
-				offsetParent = offsetParent.parentNode;
+				offsetParent = offsetParent.offsetParent || doc.documentElement;
 			}
-			if ( offsetParent && offsetParent !== elem && offsetParent.nodeType === 1 ) {
+			if ( offsetParent && offsetParent !== elem && offsetParent.nodeType === 1 &&
+				jQuery.css( offsetParent, "position" ) !== "static" ) {
 
 				// Incorporate borders into its offset, since they are outside its content origin
 				parentOffset = jQuery( offsetParent ).offset();

test/unit/offset.js

@@ -436,13 +436,16 @@ testIframe( "fixed", "offset/fixed.html", function( assert, $, window ) {
 } );
 
 testIframe( "table", "offset/table.html", function( assert, $ ) {
-	assert.expect( 4 );
+	assert.expect( 6 );
 
 	assert.equal( $( "#table-1" ).offset().top, 6, "jQuery('#table-1').offset().top" );
 	assert.equal( $( "#table-1" ).offset().left, 6, "jQuery('#table-1').offset().left" );
 
 	assert.equal( $( "#th-1" ).offset().top, 10, "jQuery('#th-1').offset().top" );
 	assert.equal( $( "#th-1" ).offset().left, 10, "jQuery('#th-1').offset().left" );
+
+	assert.equal( $( "#th-1" ).position().top, 10, "jQuery('#th-1').position().top" );
+	assert.equal( $( "#th-1" ).position().left, 10, "jQuery('#th-1').position().left" );
 } );
 
 testIframe( "scroll", "offset/scroll.html", function( assert, $, win ) {