forms - Symfony-Twig: insert fontawesome icon in a form_widget -

to validate form using standard:

{{ form_widget(form.save, {'attr': {'class': 'btn btn-sm btn-danger'}, 'label': 'submit form'}) }} 

i want insert fontawsome icon in button. tried:

{{ form_widget(form.save, {'attr': {'class': 'btn btn-sm btn-danger'}, 'label': '<i class="fa fa-envelope-o"></i> submit form'}) }} 

but not working; obviously

any idea how that?

i define new form template in same view (or in template if need reuse code). more details here

{% extends '::base.html.twig' %}  {% form_theme form _self %}  {%- block submit_widget -%}     {%- set type = type|default('submit') -%}      {%- if label empty -%}         {%- if label_format not empty -%}             {% set label = label_format|replace({                 '%name%': name,                 '%id%': id,             }) %}         {%- else -%}             {% set label = name|humanize %}         {%- endif -%}     {%- endif -%}     <button type="{{ type|default('button') }}" {{ block('button_attributes') }}>         <i class="fa fa-envelope-o"></i>         {{ label|trans({}, translation_domain) }}     </button> {%- endblock submit_widget -%}   {% block content %}     {# ... render form #}      {{ form_row(form.age) }} {% endblock %} 

edit

also, interesting customize (accept html raw in label) label submit button id. more details chapter how customize individual field of link above.

replace product_name submit id , syntax {{ form_widget(form.save, {'attr': {'class': 'btn btn-sm btn-danger'}, 'label': '<i class="fa fa-envelope-o"></i> submit form'}) }}

{% block _product_name_label %}      <label>{{ label|raw }}</label> {% endblock %}