firefly-iii/resources/views/v1/budgets/budget-limits/create.twig

<div class="modal-dialog">
    <div class="modal-content">
        <div class="modal-header">
            <button type="button" class="close" data-dismiss="modal"><span>&times;</span><span class="sr-only">{{ 'close'|_ }}</span>
            </button>
            <h4 class="modal-title">
                {{ trans('firefly.set_budget_limit_title',
                    {start: start.formatLocalized(monthAndDayFormat), end: end.formatLocalized(monthAndDayFormat), budget: budget.name}) }}
            </h4>
        </div>

        <form style="display: inline;" id="income" action="{{ route('budget-limits.store') }}" method="POST">
            <div class="modal-body">
                <input type="hidden" name="_token" value="{{ csrf_token() }}"/>
                <input type="hidden" name="start" value="{{ start.format('Y-m-d') }}"/>
                <input type="hidden" name="end" value="{{ end.format('Y-m-d') }}"/>
                <input type="hidden" name="budget_id" value="{{ budget.id }}"/>
                <div class="form-group">
                    <select class="form-control" name="transaction_currency_id">
                        {% for currency in currencies %}
                            <option label="{{ currency.name }}" value="{{ currency.id }}">{{ currency.name }}</option>
                        {% endfor %}
                    </select>
                </div>
                <div class="form-group">
                    <input step="any" class="form-control" id="amount" value="" autocomplete="off" name="amount" type="number"/>
                </div>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">{{ 'close'|_ }}</button>
                <button type="submit" class="btn btn-primary">{{ 'set_budget_limit'|_ }}</button>
            </div>
        </form>
    </div>
</div>