Example of using bleach to strip out bad/evil code.

html_tags.py

from django import template
from django.utils.safestring import mark_safe
import bleach

register = template.Library()


@register.filter
def strip_tags(text, valid_tags=['p', 'a', 'strong', 'em', 'ol', 'ul', 'li']):
    if not isinstance(valid_tags, list):
        valid_tags = valid_tags.split(',')
    text = bleach.clean(text, valid_tags)
    return mark_safe(text)