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Using Template Specific JavaScript in Django

I have a base_generic.html page in django that has the standard UI elements (navbar, footer, etc.), and I have a list.html page which extends the base_generic.html page. The list.html page is using a javascript function that is only used in this page, but for it to work, I have to include it in the base_generic.html page.
How can I include this javascript function in list.html using Django's built-in template tags and features?
Should I use {% verbatim %} or {% scripts %} or another tag template?
Should I include this inline with the {% block content %} that has the html for this django template, or should I place it before or after the {% block content %}?

You have several ways of accomplish what you want:
Just add the javascript snippet inside the {% block content %}
{% block content %}
my javascript();
{% endblock content %}
Use the include statement to a file with your javascript, again, inside the {% block content %}
{% include 'my_javascript.html' %}
In this way, you can reuse your javascript code on other pages.
Create a new block in base_generic.html, like:
{% block my_javascript %}{% endblock my_javascript %}
And in you child template, add the javascript as told in the first points iside these tags, in this case it can be outside or inside the {% block content %}.

An alternative would be pass the path for the js file in your views.py:
context = {
'scripts_to_include':['/static/js/my_js_file.js']
}
You can obviously include multiple js files here. Then, in your template:
{% if scripts_to_include %}
{% for script_url in scripts_to_include %}
<script src="{{script_url}}"></script>
{% endfor %}
{% endif %}
I like this, cause the js files can still be stored in a directory (instead of putting it right into html), JS files are also reusable.

Separating JavaScripts file in symfony4 twig templates

I have a question about, how to separate a loading specify javascript file of specify template twig file.
I got for example admin.html.twig which extends base.html.twig, in base i got
{% block javascripts %}
<script src="/assets/js/core/jquery.min.js"></script>
<script src="/assets/js/core/popper.min.js"></script>
<script src="/assets/js/core/bootstrap-material-design.min.js"></script>
<script src="/assets/js/plugins/perfect-scrollbar.jquery.min.js"></script>
<script async defer src="https://buttons.github.io/buttons.j"></script>
<script src="/assets/js/plugins/chartist.min.js"></script>
<script src="/assets/js/plugins/bootstrap-notify.js"></script>
<script src="/assets/js/material-dashboard.min.js"></script>
<script src="/assets/demo/jquery.sharrre.js"></script>
<script src="/assets/js/sparkline.js"></script>
<script src="/assets/js/plugins/chartjs.min.js"></script>
{% endblock %}
and I got next file like dashboard.html.twig which extends a admin.html.twig file, and my question is that in dashboard.html.twig file i got at the a little writed-self small javascript code, and this javascript of course use a jquery library but this library i loaded in base.html.twig file a next of my selfwrited script which is in dashboard.html.twig.
My question is, how i can for example load my small code of javascript (of course i can save it in separated file like mycode.js) but how to load only when this route of dashboard.html.twig file i used and after jquery is loaded ? becouse in another routers i dont need this mycode.js so I dont wanna put it to base.html.twig file in javascript block, any idea ?

If dashboard directly extends admin then u can do the following to ensure to load all the admin scripts and to add the dashboard specific script:
{% extends "admin.html.twig" %}
{% block javascripts %}
{{ parent() }} {# execute the parent block, thus loading all scripts in admin #}
<script src="/assets/js/dashboard/mycode.js"></script>
{% endblock %}

You can dived
{% extends "admin.html.twig" %} {# use only in case your all templates are at the same places like app/Resources/views/admin.html.twig #}
{% block javascripts %}
{{ parent() }} {# loads the parent javascript block, from the template you are extending in first line. #}
<script src="/assets/js/dashboard/code.js"></script>
{% endblock %}
in case you are trying to extend a template from another bundle then you can use this
{% extends "YourBundleName:Default:admin.html.twig" %} {# YourControllerRelativeName just in case your view structure is like views/Default/admin.html.twig#}
{% block javascripts %}
{{ parent() }} {# loads the parent javascript block, from the template you are extending in first line. #}
<script src="/assets/js/dashboard/code.js"></script>
{% endblock %}
to the better understanding you should read a little here:
https://symfony.com/doc/2.8/templating.html
Note:- in the documents you should change version as per your current version.

I would suggest the following solution.
Declare the following block in base.html.twig after {% block javascripts %}{% endblock %}
{% block javascript_page %}{# specific code for current page #}{% endblock %}
Then in your page you can include page specific scripts
{% extends "admin.html.twig" %} or {% extends "base.html.twig" %}
{% block javascript_page %}
<script src="/assets/js/pages/my_page.js"></script>
{% endblock %}
Although answer by DarkBee is also correct but in this way you don't have to worry about calling {{ parent() }} in each page.

Django extended template is not loading base JS at time

I've in Django 1.11 a base.html which contains all the scripts references.
Then, I've another page.html that extendes base.html with {% extends base.html %} and {% block content %} / {% endblock content %} tags.
Well. In base.html I've a reference to Chartjs.js plugin. In page.html, if I try to call to Chart() function or just $ jquery, I get "function is not defined". If I open console debugger and try to call $ or just Chart(), it works. So I think that there's a problem with loading time. The page.html is rendered before the js are downloaded or requested!
How can I solve it? I've done it before, I don't know what could be the problem.
Thanks!

Without your code showing, hard to tell. Based on what you wrote, perhaps you forgot to put a block and block.super to get the parent (base.html's) Chartjs reference.
This should be in your page.html at the bottom after your {% endblock content %} tag. See example below (using DataTables as example since your code is not shown):
</div>
{% endblock content %}
{% block javascript %}
{{ block.super }}
<script type="application/javascript">
$(document).ready(function () {
$('#table').DataTable({
responsive: true,
});
});
</script>
{% endblock javascript %}
Base.html would have the js section enclosed in
{% block javascript %} …. {% endblock javascript %}

Combine javascripts from multiple templates with Assetic

Suppose I have the following twig templates:
base.html.twig:
<html>
<body>
{% block javascripts %}
{% javascripts
'../app/Resources/js/jquery-2.2.4.min.js'
'../app/Resources/js/base.js'
filter='uglifyjs2' output='main.js'
%}
<script src="{{ asset_url }}" type="text/javascript"></script>
{% endjavascripts %}
{% endblock javascripts %}
</body>
</html>
page1.html.twig:
{% extends 'base.html.twig' %}
{% block javascripts %}
{{ parent() }}
{% javascripts
'../app/Resources/js/page1_specific.js'
'../app/Resources/js/page1_other.js'
filter='uglifyjs2' output='page1.js'
%}
<script src="{{ asset_url }}" type="text/javascript"></script>
{% endjavascripts %}
{% endblock javascripts %}
With this code, page1 template will make two javascript requests, one for main.js and another one for page1.js.
Is it possible to write it differently, so I it would generate only one big js file specific to each final template, including the base page js and the page1 specific js?

You can declare in your config.yml the base js, like this:
assetic:
assets:
base:
inputs:
- '#AppBundle/Resources/public/js/jquery-2.2.4.min.js'
- '#AppBundle/Resources/public/js/base.js'
And call this in your javascript block:
{% javascripts
'#base'
'../app/Resources/js/page1_specific.js'
'../app/Resources/js/page1_other.js'
filter='uglifyjs2' output='page1.js'
%}
You can find more info here.

how to organize JS files in Django?

I am currently working with a Django project, I include different libraries JS and I create JS files for manage the other libraries, but I don't know the correct organization of JS files for each html page, for example, I have a "Main.js" and "Milk.js" in base template but I don't want have both files in the same base template, I want separate files for each page..
I tried adding as a normal js file
<script src="{{ STATIC_URL }}js/milk.js"></script>
But it show me a error message asking me several dependencies when inherited from base.html
I hope your help
EDITED:
Cuando he añadido en mis archivos de plantillas, sin mostrarme error en la consola de cromo pero en la consola django mostrarme los archivos JS de carga con 304 error.
The libraries are in base.html
it's strange, I can load milk.js when I click from home.html but when I will click in other page for example "cow.html" from "Milk.html" no load js file even when I did the same as "milk.html".

Django template engine has already provided a tag for inherit your HTML structure called 'extend'.
Tag "extends" is a using for extends a parent template.
{% extends "base.html" %} uses the literal value "base.html" as the name of the parent template to extend.
base.html is the parent template that can extendable.
{% load staticfiles %}
<html lang="en">
<head><title>Hello World</title></head>
<body>
<div id="content">
{% block content %}{% endblock %}
</div>
{% block scripts %}
<script src="{% static 'js/main.js' %}"></script>
{% endblock %}
</body>
</html>
and you have another HTML called milk.html that you need everything same as the base.html but include milk.js you just do something like this.
{% load staticfiles %}
{% extends "base.html" %}
{% block scripts %}
<!-- block.super will get the content of the block from the parent template -->
{{ block.super }}
<script src="{% static 'js/milk.js' %}"></script>
{% endblock %}
Read more about docs[1]: [1]: https://docs.djangoproject.com/en/dev/ref/templates/builtins/#std:templatetag-extends

In your base.html file, add a block inside the head tag like this:
{% block scripts %}
<!-- some default content here -->
{% endblock %}
Now in your different templates files:
{% block scripts %}
<!-- insert per template scripts here -->
{% endblock %}
So in the templates with Milk, it would be like:
{% block scripts %}
<script src="{{ STATIC_URL }}js/milk.js"></script>
{% endblock %}

Being lazy, and extending the admin templates with {% extends admin/base.html %} I found that using {% block scripts %} did not work. The JavaScript was not sent to the browser. However base.html has a built-in block {% block extrahead %} which is empty and just the ticket for inserting additional content like scripts into the header.
{% block extrahead %}
<script src="{{ STATIC_URL }}js/milk.js"></script>
{% endblock %}