Click on the Admin Bar to scroll to top

scrolltotop.php

<?php
function ds_admin_bar_scrolltop() {
	if ( ! is_admin_bar_showing() )
		return;
	
	?>
<script>
( function( $ ) {
	$( '#wpadminbar' ).click( function() {
		$( 'html, body' ).animate( { scrollTop: 0 }, 100 );
	} );
	$( '#wpadminbar li' ).click( function( e ) { 
		e.stopPropagation(); 
	} );
} )( jQuery );
</script>
	<?php
}
add_action( 'admin_print_footer_scripts', 'ds_admin_bar_scrolltop' );