"pattern" in "input" is not modified

[Jakobhenningjensen]

In the following

      <div class="form-group">
        {{form.link|attr:"pattern:[a-z]{4,8}"|as_crispy_field}}
      </div>

I would assume it to accept 4-8 lowercase letters, but writing "aaaa" still renders in invalid.

I have tried removing the pattern

{{form.link|remove_attr:"pattern"|as_crispy_field}}

or set it to anything

{{form.link|attr:"pattern:.*"|as_crispy_field}}

but it still only accepts the default pattern