如何使用JSON信息验证Javascript中的表单输入数据

var validationRules = {
  "name": {
    "required": true,
    "minLength": 2,
    "maxLength": 20
  },
  "email": {
    "required": true,
    "pattern": /^[^\s@]+@[^\s@]+\.[^\s@]+$/
  },
  "password": {
    "required": true,
    "minLength": 6
  }
};

var form = document.getElementById("myForm");

form.addEventListener("submit", function(event) {
  event.preventDefault(); // 阻止表单默认提交行为

  var formData = new FormData(form);
  var errors = validateFormData(formData);

  if (Object.keys(errors).length === 0) {
    // 表单数据验证通过，可以进行提交操作
    form.submit();
  } else {
    // 显示错误信息
    displayErrors(errors);
  }
});

function validateFormData(formData) {
  var errors = {};

  for (var key in validationRules) {
    if (validationRules.hasOwnProperty(key)) {
      var rules = validationRules[key];
      var value = formData.get(key);

      for (var rule in rules) {
        if (rules.hasOwnProperty(rule)) {
          var isValid = true;

          switch (rule) {
            case "required":
              isValid = value.trim() !== "";
              break;
            case "minLength":
              isValid = value.length >= rules[rule];
              break;
            case "maxLength":
              isValid = value.length <= rules[rule];
              break;
            case "pattern":
              isValid = rules[rule].test(value);
              break;
            // 添加其他验证规则的处理逻辑
          }

          if (!isValid) {
            if (!errors[key]) {
              errors[key] = [];
            }
            errors[key].push(rule);
          }
        }
      }
    }
  }

  return errors;
}

function displayErrors(errors) {
  var errorContainer = document.getElementById("errorContainer");
  errorContainer.innerHTML = ""; // 清空之前的错误信息

  for (var key in errors) {
    if (errors.hasOwnProperty(key)) {
      var errorMessages = errors[key];

      for (var i = 0; i < errorMessages.length; i++) {
        var errorMessage = getErrorMessage(key, errorMessages[i]);
        var errorElement = document.createElement("p");
        errorElement.textContent = errorMessage;
        errorContainer.appendChild(errorElement);
      }
    }
  }
}

function getErrorMessage(fieldName, rule) {
  var errorMessages = {
    "name": {
      "required": "请输入姓名",
      "minLength": "姓名长度不能少于2个字符",
      "maxLength": "姓名长度不能超过20个字符"
    },
    "email": {
      "required": "请输入邮箱",
      "pattern": "请输入有效的邮箱地址"
    },
    "password": {
      "required": "请输入密码",
      "minLength": "密码长度不能少于6个字符"
    }
  };

  return errorMessages[fieldName][rule];
}