Scroll left toc to active entry

Useful when the left-side toc is longer than the screen.
Fixes google#348 and google#257

This is an update of the original patch of narrenfrei

layouts/partials/sidebar-tree.html

@@ -53,9 +53,9 @@
 <li class="td-sidebar-nav__section-title td-sidebar-nav__section{{ if $withChild }} with-child{{ else }} without-child{{ end }}{{ if $activePath }} active-path{{ end }}{{ if (not (or $show $p.Site.Params.ui.sidebar_menu_foldable )) }} collapse{{ end }}" id="{{ $mid }}-li">
   {{ if (and $p.Site.Params.ui.sidebar_menu_foldable (ge $ulNr 1)) -}}
   <input type="checkbox" id="{{ $mid }}-check"{{ if $activePath}} checked{{ end }}/>
-  <label for="{{ $mid }}-check"><a href="{{ $manualLink }}"{{ if ne $s.LinkTitle $manualLinkTitle }} title="{{ $manualLinkTitle }}"{{ end }}{{ with $s.Params.manualLinkTarget }} target="{{ . }}"{{ if eq . "_blank" }} rel="noopener"{{ end }}{{ end }} class="align-left pl-0 {{ if $active}} active{{ end }} td-sidebar-link{{ if $s.IsPage }} td-sidebar-link__page{{ else }} td-sidebar-link__section{{ end }}{{ if $treeRoot }} tree-root{{ end }}" id="{{ $mid }}">{{ with $s.Params.Icon}}<i class="{{ . }}"></i>{{ end }}<span class="{{ if $active }}td-sidebar-nav-active-item{{ end }}">{{ $s.LinkTitle }}</span></a></label>
+  <label for="{{ $mid }}-check"><a href="{{ $manualLink }}"{{ if ne $s.LinkTitle $manualLinkTitle }} title="{{ $manualLinkTitle }}"{{ end }}{{ with $s.Params.manualLinkTarget }} target="{{ . }}"{{ if eq . "_blank" }} rel="noopener"{{ end }}{{ end }} class="align-left pl-0 {{ if $active}} active{{ end }} td-sidebar-link{{ if $s.IsPage }} td-sidebar-link__page{{ else }} td-sidebar-link__section{{ end }}{{ if $treeRoot }} tree-root{{ end }}" id="{{ $mid }}">{{ with $s.Params.Icon}}<i class="{{ . }}"></i>{{ end }}<span {{ if $active }}class="td-sidebar-nav-active-item" id="td-sidebar-nav-active-item"{{ end }}>{{ $s.LinkTitle }}</span></a></label>
   {{ else -}}
-  <a href="{{ $manualLink }}"{{ if ne $s.LinkTitle $manualLinkTitle }} title="{{ $manualLinkTitle }}"{{ end }}{{ with $s.Params.manualLinkTarget }} target="{{ . }}"{{ if eq . "_blank" }} rel="noopener"{{ end }}{{ end }} class="align-left pl-0{{ if $active}} active{{ end }} td-sidebar-link{{ if $s.IsPage }} td-sidebar-link__page{{ else }} td-sidebar-link__section{{ end }}{{ if $treeRoot }} tree-root{{ end }}" id="{{ $mid }}">{{ with $s.Params.Icon}}<i class="{{ . }}"></i>{{ end }}<span class="{{ if $active }}td-sidebar-nav-active-item{{ end }}">{{ $s.LinkTitle }}</span></a>
+  <a href="{{ $manualLink }}"{{ if ne $s.LinkTitle $manualLinkTitle }} title="{{ $manualLinkTitle }}"{{ end }}{{ with $s.Params.manualLinkTarget }} target="{{ . }}"{{ if eq . "_blank" }} rel="noopener"{{ end }}{{ end }} class="align-left pl-0{{ if $active}} active{{ end }} td-sidebar-link{{ if $s.IsPage }} td-sidebar-link__page{{ else }} td-sidebar-link__section{{ end }}{{ if $treeRoot }} tree-root{{ end }}" id="{{ $mid }}">{{ with $s.Params.Icon}}<i class="{{ . }}"></i>{{ end }}<span {{ if $active }}class="td-sidebar-nav-active-item" id="td-sidebar-nav-active-item"{{ end }}>{{ $s.LinkTitle }}</span></a>
   {{- end }}
   {{- if $withChild }}
   {{- $ulNr := add $ulNr 1 }}
@@ -68,4 +68,9 @@
   </ul>
   {{- end }}
 </li>
-{{- end }}
+{{- end }}
+
+<script>
+var myElement = document.getElementById('td-sidebar-nav-active-item');
+myElement.scrollIntoView();
+</script>