How to write jquery form validation

In front-end development, form validation is an essential skill. Form validation can ensure the correctness and legality of data entered by users, effectively reducing the probability of data errors and bringing a good experience to users. This article will introduce how to use jQuery to validate forms.

Frameworks and plug-ins

When using jQuery to validate forms, we can choose to use some excellent frameworks and plug-ins to improve development efficiency and code quality. Common form validation frameworks and plug-ins are:

1. jQuery Validation
   jQuery Validation is a very popular form validation plug-in, which can automatically validate the data in the form through simple settings and principles. In addition, jQuery Validation supports multiple validation types, including required fields, minimum length, maximum length, regular expressions, remote validation, etc.
2. Bootstrap Validator
   Bootstrap Validator is a form validation plug-in based on Bootstrap and jQuery. It provides a variety of verification methods, including required fields, email, password, mobile phone number, URL address, etc., and supports custom verification rules.
3. FormValidation
   FormValidation is a popular form validation framework, which is characterized by integrating different JavaScript libraries and frameworks, such as Bootstrap and Foundation. FormValidation supports custom error messages, asynchronous validation, convenient validation methods and multiple validation rules.

The above three frameworks and plug-ins are easy to use, flexible and changeable, and deserve the attention of developers.

Implementation of form validation

The following will take the jQuery Validation plug-in as an example to introduce how to use jQuery to validate the form.

1. Introducing jQuery and jQuery Validation

Before we begin, we need to introduce the necessary JavaScript files into our HTML file.

<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script src="https://cdn.jsdelivr.net/jquery.validation/1.16.0/jquery.validate.min.js"></script>

2. Writing HTML code

In the HTML code, we need to first define a form and add a unique ID to each form element.

<form id="myform">
  <label for="username">用户名:</label>
  <input type="text" id="username" name="username"><br>

  <label for="password">密码:</label>
  <input type="password" id="password" name="password"><br>

  <label for="email">电子邮件:</label>
  <input type="email" id="email" name="email"><br>

  <button type="submit">提交</button>
</form>

3. Write JavaScript code

In the JavaScript code, we need to first configure the validation rules and error message, and then call the validate() method to validate the form. If the form validation is successful, corresponding operations can be performed, such as submitting the form.

$(document).ready(function() {
  $("#myform").validate({
    rules: {
      username: {
        required: true,
        minlength: 6
      },
      password: {
        required: true,
        minlength: 8
      },
      email: {
        required: true,
        email: true
      }
    },
    messages: {
      username: {
        required: "请输入用户名",
        minlength: "用户名长度必须大于等于6个字符"
      },
      password: {
        required: "请输入密码",
        minlength: "密码长度必须大于等于8个字符"
      },
      email: {
        required: "请输入电子邮件",
        email: "请正确填写有效的电子邮件地址"
      }
    },
    submitHandler: function(form) {
      // 表单通过验证后执行的操作
      form.submit();
    }
  });
});

In the above code, we use the validate() method to validate the form, where the rules attribute defines the validation rules and the messages attribute defines the corresponding error message. When the form is submitted, the submitHandler attribute triggers related operations.

It should be noted that when using jQuery Validation for form validation, you need to introduce jQuery and jQuery Validation scripts into the HTML file first, and execute the code after jQuery is ready. In addition, you also need to set a unique ID for each form element to associate with the validation rules.

Summary

Through this article we learned how to use the jQuery Validation plug-in to validate the form, as well as common form validation frameworks and plug-ins. In actual development, we can choose the appropriate form verification method according to the specific situation, and use a variety of verification rules and error prompts to ensure the correctness and security of the form data.

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