How can I customize jQuery validation in ASP.NET?

How can I customize jQuery validation in ASP.NET?

You can customize jQuery validation in ASP.NET by using the $.validator.addMethod function to create custom validation methods.

Can you give me an example of a custom validation method?

Sure! Here's a simple example:

$.validator.addMethod('customEmail', function(value, element) {
    return this.optional(element) || /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/.test(value);
});

This method checks if the input is a valid email format.

How do I apply this custom method to a form field?

You can apply it by adding the data-rule-customEmail attribute to your input field in the form, like this:

<input type='text' name='email' data-rule-customEmail='true' />

What if I want to display a custom error message?

You can specify a custom error message using the messages option:

$('form').validate({
    rules: {
        email: {
            required: true,
            customEmail: true
        }
    },
    messages: {
        email: {
            required: 'Email is required',
            customEmail: 'Please enter a valid email address'
        }
    }
});