{% block title %}The Page Title{% endblock %}

Tips and Tricks =============== .. highlight:: html+jinja This part of the documentation shows some tips and tricks for Jinja2 templates. .. _null-master-fallback: Null-Master Fallback -------------------- Jinja2 supports dynamic inheritance and does not distinguish between parent and child template as long as no `extends` tag is visited. While this leads to the surprising behavior that everything before the first `extends` tag including whitespace is printed out instead of being igored, it can be used for a neat trick. Usually child templates extend from one template that adds a basic HTML skeleton. However it's possible put the `extends` tag into an `if` tag to only extend from the layout template if the `standalone` variable evaluates to false which it does per default if it's not defined. Additionally a very basic skeleton is added to the file so that if it's indeed rendered with `standalone` set to `True` a very basic HTML skeleton is added:: {% if not standalone %}{% extends 'master.html' %}{% endif -%} {% block title %}The Page Title{% endblock %} {% block body %}

This is the page body.

{% endblock %} Alternating Rows ---------------- If you want to have different styles for each row of a table or list you can use the `cycle` method on the `loop` object::

{{ row }}

`cycle` can take an unlimited amount of strings. Each time this tag is encountered the next item from the list is rendered. Highlighting Active Menu Items ------------------------------ Often you want to have a navigation bar with an active navigation item. This is really simple to achieve. Because assignments outside of `block`\s in child templates are global and executed before the layout template is evaluated it's possible to define the active menu item in the child template:: {% extends "layout.html" %} {% set active_page = "index" %} The layout template can then access `active_page`. Additionally it makes sense to defined a default for that variable:: {% set navigation_bar = [ ('/', 'index', 'Index'), ('/downloads/', 'downloads', 'Downloads'), ('/about/', 'about', 'About') ] -%} {% set active_page = active_page|default('index') -%} ... ... .. _accessing-the-parent-loop: Accessing the parent Loop ------------------------- The special `loop` variable always points to the innermost loop. If it's desired to have access to an outer loop it's possible to alias it:: {% for row in table %} {% set rowloop = loop %} {% for cell in row %}