5 Ways to Validate 10-Digit Phone Numbers in jQuery

Validating 10-digit phone numbers in jQuery is a common requirement for ensuring data integrity in web forms. We'll explore five different ways to implement this validation, complete with working code snippets. We will also examine the pitfalls of these traditional approaches and see how Abstract API helps overcome them.

How to Validate 10-Digit Phone Numbers in jQuery

Here are four common methods to validate a 10-digit phone number with jQuery. Each approach uses different tools, from built-in rules and custom functions to browser features and plugins.

Built-in jQuery Validate Rule

The jQuery Validate plugin comes with additional methods that simplify common validation tasks. To use its built-in U.S. phone number validation, you must load both `jquery.validate.js` and `additional-methods.js`. Then, you attach the `phoneUS` rule to your phone number field.

This rule automatically strips whitespace and formatting characters from the input. It then checks the number against a regular expression that validates North American Numbering Plan formats, even allowing an optional leading country code of 1.

$('#form').validate({
  rules: {
    phone: { required: true, phoneUS: true }
  }
});

Custom jQuery Validate Rule

You can create a custom rule with the jQuery Validate plugin if you only need to confirm the input contains exactly ten digits. This involves the `$.validator.addMethod` function to define a new validator, which we can call `tenDigits`.

The function first removes all non-digit characters from the value. It then tests if the sanitized string matches the pattern for ten consecutive digits. This approach supports various input formats while it enforces the core ten-digit requirement.

$.validator.addMethod('tenDigits', function (v, el) {
  const digits = v.replace(/\D/g, '');
  return this.optional(el) || /^\d{10}$/.test(digits);
}, 'Enter a 10-digit number.');

$('#form').validate({ rules: { phone: { tenDigits: true } } });

HTML5 Constraint Validation

This method relies on the browser’s built-in form validation capabilities, with jQuery used only to trigger the check. You add a `pattern` attribute to your input field with a regular expression that defines the required format, such as `\d{3}-\d{3}-\d{4}`.

The `type="tel"` attribute is also helpful, as it prompts a numeric keypad on mobile devices for a better user experience. The browser automatically enforces the pattern when the form is submitted, and jQuery can prevent submission if the validation fails.

<input id="phone" type="tel" pattern="\d{3}-\d{3}-\d{4}" required>

$('form').on('submit', e => {
  if (!e.currentTarget.checkValidity()) e.preventDefault();
});

jQuery Inputmask Plugin

The jQuery Inputmask plugin helps guide users to enter data in a specific format. You apply a mask, like '999-999-9999', to the input field. The plugin then automatically inserts separators and blocks any keystrokes that are not digits.

For validation, you must check if the field is complete upon form submission. The plugin provides an `isComplete` method for this purpose. The plugin also offers a 'phone' alias for international formats, which adds more flexibility than a fixed mask.

$('#phone').inputmask('999-999-9999', { clearIncomplete: true });

$('form').on('submit', e => {
  if (!$('#phone').inputmask('isComplete')) e.preventDefault();
});

Challenges of jQuery Phone Number Validation

These jQuery methods appear simple, but they introduce practical challenges that compromise data quality. The approaches often fall short when they encounter real-world phone number variations and complexities.

• A custom `tenDigits` rule fails internationally because it only recognizes the North American plan. It rejects valid numbers under the E.164 standard and even blocks U.S. toll-free formats that include a country code.
• The built-in `phoneUS` rule uses hard-coded logic that quickly becomes obsolete. The North American Numbering Plan constantly evolves with new area codes, which causes the plugin to misclassify valid numbers over time.
• The Inputmask plugin and HTML5 pattern attribute require a fixed format. Users who paste numbers with different punctuation or spacing break the validation. To support all formats, you must maintain many complex pattern variations.
• All jQuery methods only test a number’s format, not its authenticity. They cannot detect disconnected lines or recently ported VoIP numbers. True validation requires a server-side lookup to confirm the number is active.