tghelere

<template>
    <div>
        <b-form @submit.prevent="onSubmit" class="m50">
            <b-row>                   
                <b-col md="4">
                    <b-form-group>
                        <b-form-select @input="getCities(form.state.id)" id="states" required v-model="form.state" :options="states">
                            <template slot="first">
                                <option :value="null" disabled>UF *</option>
                            </template>

nulldreams

<template>
  <b-container class="formulario">
    <b-form>
    
      <b-form-group label="Estados">
        <b-form-select v-model="estado" :options="estados" class="mb-3"></b-form-select>
      </b-form-group>
      
      <b-form-group label="Cidade">
        <b-form-select v-model="cidade" :options="cidades" class="mb-3"></b-form-select>