{% load icons_tags %}

{% icons_get_icon 'mayan.apps.forms.icons.icon_color_random' as icon_color_random %}

<div class="input-group">
    {% include "django/forms/widgets/input.html" %}
    <div class="input-group-addon views-widget-color-random">{{ icon_color_random }}</div>
</div>

<script>
    'use strict';

    jQuery(document).ready(function() {
        $('.views-widget-color-random').click(function (event) {
            let randomColor = Math.floor(
                Math.random() * 16777215
            ).toString(16);
            $(this).parent().children('input').val('#' + randomColor);
        });
    });
</script>