diff --git a/ui/jquery.ui.position.js b/ui/jquery.ui.position.js
index a5dc3183438..dbfadedd169 100644
--- a/ui/jquery.ui.position.js
+++ b/ui/jquery.ui.position.js
@@ -29,10 +29,41 @@ function getOffsets( offsets, width, height ) {
 		parseInt( offsets[ 1 ], 10 ) * ( rpercent.test( offsets[ 1 ] ) ? height / 100 : 1 )
 	];
 }
+
 function parseCss( element, property ) {
 	return parseInt( $.css( element, property ), 10 ) || 0;
 }
 
+function getDimensions( elem ) {
+	var raw = elem[0];
+	if ( raw.nodeType === 9 ) {
+		return {
+			width: elem.width(),
+			height: elem.height(),
+			offset: { top: 0, left: 0 }
+		};
+	}
+	if ( $.isWindow( raw ) ) {
+		return {
+			width: elem.width(),
+			height: elem.height(),
+			offset: { top: elem.scrollTop(), left: elem.scrollLeft() }
+		};
+	}
+	if ( raw.preventDefault ) {
+		return {
+			width: 0,
+			height: 0,
+			offset: { top: raw.pageY, left: raw.pageX }
+		};
+	}
+	return {
+		width: elem.outerWidth(),
+		height: elem.outerHeight(),
+		offset: elem.offset()
+	};
+}
+
 $.position = {
 	scrollbarWidth: function() {
 		if ( cachedScrollbarWidth !== undefined ) {
@@ -91,32 +122,21 @@ $.fn.position = function( options ) {
 	// make a copy, we don't want to modify arguments
 	options = $.extend( {}, options );
 
-	var atOffset, targetWidth, targetHeight, targetOffset, basePosition,
+	var atOffset, targetWidth, targetHeight, targetOffset, basePosition, dimensions,
 		target = $( options.of ),
 		within = $.position.getWithinInfo( options.within ),
 		scrollInfo = $.position.getScrollInfo( within ),
-		targetElem = target[0],
 		collision = ( options.collision || "flip" ).split( " " ),
 		offsets = {};
 
-	if ( targetElem.nodeType === 9 ) {
-		targetWidth = target.width();
-		targetHeight = target.height();
-		targetOffset = { top: 0, left: 0 };
-	} else if ( $.isWindow( targetElem ) ) {
-		targetWidth = target.width();
-		targetHeight = target.height();
-		targetOffset = { top: target.scrollTop(), left: target.scrollLeft() };
-	} else if ( targetElem.preventDefault ) {
+	dimensions = getDimensions( target );
+	if ( target[0].preventDefault ) {
 		// force left top to allow flipping
 		options.at = "left top";
-		targetWidth = targetHeight = 0;
-		targetOffset = { top: targetElem.pageY, left: targetElem.pageX };
-	} else {
-		targetWidth = target.outerWidth();
-		targetHeight = target.outerHeight();
-		targetOffset = target.offset();
 	}
+	targetWidth = dimensions.width;
+	targetHeight = dimensions.height;
+	targetOffset = dimensions.offset;
 	// clone to reuse original targetOffset later
 	basePosition = $.extend( {}, targetOffset );