takahe/templates/activities/_image_upload.html

<form
    hx-encoding='multipart/form-data'
    hx-post='{% url "compose_image_upload" %}'
    hx-target="this"
    hx-swap="outerHTML"
    _="on htmx:xhr:progress(loaded, total)
        set #attachmentProgress.value to (loaded/total)*100">
    {% csrf_token %}
    {% include "forms/_field.html" with field=form.image %}
    {% include "forms/_field.html" with field=form.description %}
    <div class="buttons">
        <button id="upload" _="on click show #attachmentProgress with display:block then hide me">Upload</button>
        <progress id="attachmentProgress" value="0" max="100"></progress>
    </div>
</form>