表单验证实现

<template>
  <div class="login-container">
    <el-form
        ref="formRef"
        :rules="rules"
        :model="form"
        class="login-form"
    >
      <div class="title-container">
          <h3 class="title">Java1234Mall-管理员登录</h3>
      </div>
      <el-form-item prop="userName">
<!--        <el-icon :size="20" class="svg-container">-->
<!--            <edit/>-->
<!--        </el-icon>-->
        <svg-icon icon="user" class="svg-container"></svg-icon>
        <el-input v-model="form.userName" placeholder="请输入用户名..."/>
      </el-fo