转自：https://www.it610.com/article/1279903369556672512.htm

1.在 标签中绑定 :rules=“方法名称”,然后在 data 里写规则

2.在 标签绑定 prop=“规则名”

<template>
        <!-- 登陆表单区域 -->
        <el-form :model="loginForm" :rules="loginFormRules">
            <!-- 用户名 -->
            <el-form-item prop="username">
                <el-input v-model="loginForm.username"></el-input>
            </el-form-item>
            <!-- 密码 -->
            <el-form-item prop="password">
                <el-input v-model="loginForm.password" type="password"></el-input>
            </el-form-item>
            <!-- 按钮区域 -->
            <el-form-item >
                <el-button type="primary">登陆</el-button>
                <el-button type="info">重置</el-button>
            </el-form-item>
        </el-form>
</template>

<script>
export default {
    data() {
        return {
            // 这是登陆表单的数据绑定对象
            loginForm: {
                username: '',
                password: ''
            },
            // 这是表单的验证规则
            loginFormRules: {
                username: [
                     // trigger: 'blur' -> 失去焦点触发
                    { required: true, message: '请输入登陆名称', trigger: 'blur' },
                    { min: 3, max: 10, message: '长度在 3 到 10 个字符', trigger: 'blur' }
                ],
                password: [
                    { required: true, message: '请输入登陆密码', trigger: 'blur' },
                    { min: 6, max: 15, message: '长度在 6 到 15 个字符', trigger: 'blur' }
                ]
            }
        }
    }
}
</script>