network_inventory/devices/templates/devices/device_update.html

{% extends "core/base.html" %}
{% load crispy_forms_tags %}

{% block section_title %}Edit Device{% endblock %}
{% block content %}
<form method="post">
<div class="row">
    {% csrf_token %}
    <div class="col">
        <div class="card mt-3">
            <div class="card-body">
            {{ form|crispy }}
            </div>
        </div>
    </div>
</div>
<br>
<input type="submit" value="Save" class="btn btn-primary">
<a href="{{ request.META.HTTP_REFERER }}" class="btn btn-primary">Cancel</a>
<input type="hidden" id="previous_page" name="previous_page" value="/previous/page/url">
</form>
<script>
    prev = document.getElementById("previous_page");
    prev.value = document.referrer;
</script>

{% endblock %}