diff --git a/themes/twentyfifteen/js/functions.js b/themes/twentyfifteen/js/functions.js
index 756fbe4..be6515f 100644
--- a/themes/twentyfifteen/js/functions.js
+++ b/themes/twentyfifteen/js/functions.js
@@ -77,9 +77,11 @@
 	} )();
 
 	/**
-	 * @summary Add or remove ARIA attributes.
+	 * Add or remove ARIA attributes.
+	 *
 	 * Uses jQuery's width() function to determine the size of the window and add
 	 * the default ARIA attributes for the menu toggle if it's visible.
+	 *
 	 * @since Twenty Fifteen 1.1
 	 */
 	function onResizeARIA() {
@@ -95,71 +97,29 @@
 	}
 
 	// Sidebar scrolling.
-	function resize() {
-		windowWidth = $window.width();
-
-		if ( 955 > windowWidth ) {
-			top = bottom = false;
-			$sidebar.removeAttr( 'style' );
-		}
-	}
-
-	function scroll() {
-		var windowPos = $window.scrollTop();
-
-		if ( 955 > windowWidth ) {
-			return;
-		}
-
-		sidebarHeight = $sidebar.height();
-		windowHeight  = $window.height();
-		bodyHeight    = $body.height();
-
-		if ( sidebarHeight + adminbarOffset > windowHeight ) {
-			if ( windowPos > lastWindowPos ) {
-				if ( top ) {
-					top = false;
-					topOffset = ( $sidebar.offset().top > 0 ) ? $sidebar.offset().top - adminbarOffset : 0;
-					$sidebar.attr( 'style', 'top: ' + topOffset + 'px;' );
-				} else if ( ! bottom && windowPos + windowHeight > sidebarHeight + $sidebar.offset().top && sidebarHeight + adminbarOffset < bodyHeight ) {
-					bottom = true;
-					$sidebar.attr( 'style', 'position: fixed; bottom: 0;' );
-				}
-			} else if ( windowPos < lastWindowPos ) {
-				if ( bottom ) {
-					bottom = false;
-					topOffset = ( $sidebar.offset().top > 0 ) ? $sidebar.offset().top - adminbarOffset : 0;
-					$sidebar.attr( 'style', 'top: ' + topOffset + 'px;' );
-				} else if ( ! top && windowPos + adminbarOffset < $sidebar.offset().top ) {
-					top = true;
-					$sidebar.attr( 'style', 'position: fixed;' );
-				}
-			} else {
-				top = bottom = false;
-				topOffset = ( $sidebar.offset().top > 0 ) ? $sidebar.offset().top - adminbarOffset : 0;
-				$sidebar.attr( 'style', 'top: ' + topOffset + 'px;' );
-			}
-		} else if ( ! top ) {
-			top = true;
-			$sidebar.attr( 'style', 'position: fixed;' );
-		}
-
-		lastWindowPos = windowPos;
-	}
-
 	function resizeAndScroll() {
-		resize();
-		scroll();
+		var windowPos = $window.scrollTop(),
+			windowHeight = $window.height(),
+			sidebarHeight = $sidebar.height(),
+			pageHeight = $( '#page' ).height();
+
+		if ( 955 < $window.width() && pageHeight > sidebarHeight && ( windowPos + windowHeight ) >= sidebarHeight ) {
+			$sidebar.css({
+				position: 'fixed',
+				bottom: sidebarHeight > windowHeight ? 0 : 'auto'
+			});
+		} else {
+			$sidebar.css('position', 'relative');
+		}
 	}
 
-	$( document ).ready( function() {
+	$( function() {
 		$body          = $( document.body );
 		$window        = $( window );
 		$sidebar       = $( '#sidebar' ).first();
-		adminbarOffset = $( '#toolbar' ).height();
 
 		$window
-			.on( 'scroll.twentyfifteen', scroll )
+			.on( 'scroll.twentyfifteen', resizeAndScroll )
 			.on( 'load.twentyfifteen', onResizeARIA )
 			.on( 'resize.twentyfifteen', function() {
 				clearTimeout( resizeTimer );
@@ -168,9 +128,7 @@
 			} );
 		$sidebar.on( 'click.twentyfifteen keydown.twentyfifteen', 'button', resizeAndScroll );
 
-		resizeAndScroll();
-
-		for ( var i = 1; i < 6; i++ ) {
+		for ( var i = 0; i < 6; i++ ) {
 			setTimeout( resizeAndScroll, 100 * i );
 		}
 	} );
diff --git a/themes/twentyfifteen/layout.html.php b/themes/twentyfifteen/layout.html.php
index c0603b3..6cecdb5 100644
--- a/themes/twentyfifteen/layout.html.php
+++ b/themes/twentyfifteen/layout.html.php
@@ -21,7 +21,7 @@
 <?php if (facebook()) { echo facebook(); } ?>
 <?php if (login()) { toolbar(); } ?>
     <div id="page" class="hfeed site">
-        <div style="top: 0px;" id="sidebar" class="sidebar">
+        <div id="sidebar" class="sidebar">
             <header id="masthead" class="site-header" role="banner">
                 <div class="site-branding">
                     <?php if (isset($is_front)) {?>
@@ -106,7 +106,7 @@
     <!--[if lte IE 8]><script type='text/javascript' src='<?php echo theme_path();?>js/html5.js'></script><![endif]-->
     <script type="text/javascript" src="<?php echo theme_path();?>js/jquery.js"></script>
     <script type="text/javascript" src="<?php echo theme_path();?>js/jquery-migrate.js"></script>
-    <script type="text/javascript" src="<?php echo theme_path();?>js/functions.js"></script>
+    <script type="text/javascript" src="<?php echo theme_path();?>js/functions.js?v=1"></script>
     <script type="text/javascript" src="<?php echo theme_path();?>js/skip-link-focus-fix.js"></script>
     <?php if (analytics()): ?><?php echo analytics() ?><?php endif; ?>
 </body>