In-depth explanation of jQuery Validate

jQuery Validate is a jQuery plugin for frontend form validation. It offers a straightforward and user-friendly set of methods to validate various types of form inputs, including required fields, length, email, phone number, and more.

1. Include jQuery and jQuery Validate plugins
   jQuery library and jQuery Validate plugins need to be included before using the jQuery Validate plugin. They can be included via CDN or downloaded locally.
2. Setting validation rules
   In an HTML form, you can set validation rules by adding specific classes to form elements. For example, adding the “required” class indicates that the form element is a required field. Multiple classes can be used to set multiple validation rules.
3. Initialize validation plugin
   In JavaScript, it is necessary to initialize the form in order to enable form validation functionality. Use the $(“#formId”).validate() method to initialize form validation.
4. Customize validation rules
   In addition to using built-in validation rules, you can also create your own custom validation rules. Use the addMethod() method to add custom validation rules. For example, you can add a validation rule to check if a password contains both letters and numbers.
5. Error message
   By default, jQuery Validate will display error messages below the form elements. You can customize the placement of error messages using the errorPlacement option. You can also customize the content of error messages using the messages option.
6. Form validation events
   You can use the submitHandler option to specify a callback function to execute after the form validation is successful. This callback function can handle form submission. You can use the invalidHandler option to specify a callback function to execute when the form validation fails.

The above is a detailed explanation of jQuery Validate. Hopefully, it will be helpful for you to understand and use the jQuery Validate plugin.