diff --git a/docs/about/release-notes.md b/docs/about/release-notes.md
index c0fbfd64..90d3f49b 100644
--- a/docs/about/release-notes.md
+++ b/docs/about/release-notes.md
@@ -46,6 +46,8 @@ The changes included in the refactor are summarized below.
   This ensures all internal links are always computed correctly regardless of
   the configuration. This also allows all internal links to be validated, not
   just links to other Markdown pages. (#842 & #872).
+* A new [url] template filter smartly ensures all URLs are relative to the
+  current page (#1526).
 * An [on_files] plugin event has been added, which could be used to include
   files not in the `docs_dir`, exclude files, redefine page URLs (i.e.
   implement extensionless URLs), or to manipulate files in various other ways.
@@ -113,42 +115,51 @@ If both `pages` and `nav` are defined, the `pages` setting will be ignored.
 
 In previous versions of MkDocs some URLs expected the [base_url] template
 variable to be prepended to the URL and others did not. That inconsistency has
-been removed. All  URLs must now be joined with the `base_url`. As previously, a
-slash must be included between the `base_url` and the URL variable. For example,
-a theme template might have previously included a link to the `site_name` as:
+been removed in that no URLs are modified before being added to the template
+context.
+
+For example, a theme template might have previously included a link to
+the `site_name` as:
 
 ```django
 <a href="{{ nav.homepage.url }}">{{ config.site_name }}</a>
 ```
 
 And MkDocs would magically return a URL for the homepage which was relative to
-the current page. That "magic" has been removed and the `base_url` must now be
-explicitly included:
+the current page. That "magic" has been removed and the [url] template filter
+should be used:
 
 ```django
-<a href="{{ base_url }}/{{ nav.homepage.url }}">{{ config.site_name }}</a>
+<a href="{{ nav.homepage.url|url }}">{{ config.site_name }}</a>
 ```
 
 This change applies to any navigation items and pages, as well as the
 `page.next_page` and `page.previous_page` attributes. For the time being, the
 `extra_javascript` and `extra_css` variables continue to work as previously
-(without `base_url`), but they have been deprecated and the corresponding
-configuration values (`config.extra_javascript` and `config.extra_css`
-respectively) should be used with `base_url` instead.
-
-Note that navigation can now include links to external sites. Obviously, the
-`base_url` should not be prepended to these items. Therefore, all navigation
-items contain a `is_link` attribute which can be used to alter the behavior for
-external links.
+(without the `url` template filter), but they have been deprecated and the
+corresponding configuration values (`config.extra_javascript` and
+`config.extra_css` respectively) should be used with the filter instead.
 
 ```django
-<a href="{% if not nav_item.is_link %}{{ base_url }}/{% endif %}{{ nav_item.url }}">{{ nav_item.title }}</a>
+{% for path in config['extra_css'] %}
+    <link href="{{ path|url }}" rel="stylesheet">
+{% endfor %}
 ```
 
-Any other URL variables which should not be used with `base_url` are explicitly
-documented as such.
+Note that navigation can now include links to external sites. Obviously, the
+`base_url` should not be prepended to these items. However, the `url` template
+filter is smart enough to recognize the URL is absolute and does not alter it.
+Therefore, all navigation items can be passed to the filter and only those that
+need to will be altered.
+
+```django
+{% for nav_item in nav %}
+    <a href="{{ nav_item.url|url }}">{{ nav_item.title }}</a>
+{% endfor %}
+```
 
 [base_url]: ../user-guide/custom-themes.md#base_url
+[url]: ../user-guide/custom-themes.md#url
 
 #### Path Based Settings are Relative to Configuration File (#543)
 
diff --git a/docs/user-guide/custom-themes.md b/docs/user-guide/custom-themes.md
index 8199f9eb..9faac59b 100644
--- a/docs/user-guide/custom-themes.md
+++ b/docs/user-guide/custom-themes.md
@@ -170,14 +170,14 @@ navigation as a nested list.
                 <ul>
                 {% for nav_item in nav_item.children %}
                     <li class="{% if nav_item.active%}current{% endif %}">
-                        <a href="{% if not nav_item.is_link %}{{ base_url }}/{% endif %}{{ nav_item.url }}">{{ nav_item.title }}</a>
+                        <a href="{{ nav_item.url|url }}">{{ nav_item.title }}</a>
                     </li>
                 {% endfor %}
                 </ul>
             </li>
         {% else %}
             <li class="{% if nav_item.active%}current{% endif %}">
-                <a href="{% if not nav_item.is_link %}{{ base_url }}/{% endif %}{{ nav_item.url }}">{{ nav_item.title }}</a>
+                <a href="{{ nav_item.url|url }}">{{ nav_item.title }}</a>
             </li>
         {% endif %}
     {% endfor %}
@@ -187,14 +187,10 @@ navigation as a nested list.
 
 #### base_url
 
-The `base_url` provides a relative path to the root of the MkDocs project.
-This makes it easy to include links to static assets in your theme. For
-example, if your theme includes a `js` folder, to include `theme.js` from that
-folder on all pages you would do this:
-
-```django
-<script src="{{ base_url }}/js/theme.js"></script>
-```
+The `base_url` provides a relative path to the root of the MkDocs project. While
+this can be used directly by prepending it to a local relative URL, it is best
+to use the [url](#url) template filter, which is smarter about how it applies
+`base_url`.
 
 #### mkdocs_version
 
@@ -285,10 +281,11 @@ documentation page.
 ##### page.url
 
 The URL of the page relative to the MkDocs `site_dir`. It is expected that this
-be used with [base_url] to ensure the URL is relative to the current page.
+be used with the [url](#url) filter to ensure the URL is relative to the current
+page.
 
 ```django
-<a href="{{ base_url }}/{{ page.url }}">{{ page.title }}</a>
+<a href="{{ page.url|url }}">{{ page.title }}</a>
 ```
 
 [base_url]: #base_url
@@ -504,6 +501,32 @@ And then displayed with this HTML in the custom theme.
 {% endif %}
 ```
 
+## Template Filters
+
+In addition to Jinja's default filters, the following custom filters are
+available to use in MkDocs templates:
+
+### url
+
+Normalizes a URL. Absolute URLs are passed through unaltered. If the URL is
+relative and the template context includes a page object, then the URL is
+returned relative to the page object. Otherwise, the URL is returned with
+[base_url](#base_url) prepended.
+
+```django
+<a href="{{ page.url|url }}">{{ page.title }}</a>
+```
+
+### tojson
+
+Safety convert a Python object to a value in a JavaScript script.
+
+```django
+<script>
+    var mkdocs_page_name = {{ page.title|tojson|safe }};
+</script>
+```
+
 ## Search and themes
 
 As of MkDocs version *0.17* client side search support has been added to MkDocs
diff --git a/mkdocs/utils/__init__.py b/mkdocs/utils/__init__.py
index ea10dc69..485781b7 100644
--- a/mkdocs/utils/__init__.py
+++ b/mkdocs/utils/__init__.py
@@ -297,6 +297,7 @@ def get_relative_url(url, other):
     relurl = posixpath.relpath(url, other)
     return relurl + '/' if url.endswith('/') else relurl
 
+
 def normalize_url(path, page=None, base=''):
     """ Return a URL relative to the given page or using the base. """
     path = path_to_url(path or '.')
diff --git a/mkdocs/utils/filters.py b/mkdocs/utils/filters.py
index 0e6e2044..ebab0ee1 100644
--- a/mkdocs/utils/filters.py
+++ b/mkdocs/utils/filters.py
@@ -7,6 +7,7 @@ from mkdocs.utils import normalize_url
 def tojson(obj, **kwargs):
     return jinja2.Markup(json.dumps(obj, **kwargs))
 
+
 @jinja2.contextfilter
 def url_filter(context, value):
     """ A Template filter to normalize URLs. """