5 Ways to Validate 10-Digit Phone Numbers in jQuery

Validating 10-digit phone numbers in jQuery is a common requirement for ensuring data quality on 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 Implement 10-Digit Phone Number Validation 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 to external plugins, to achieve the desired result.

The `phoneUS` Built-in Rule

The jQuery Validate plugin includes a helpful rule for this purpose. To use it, you must load the "jquery.validate.js" and "additional-methods.js" files. Then, you attach the validation to your form.

The "phoneUS" rule automatically removes whitespace from the input. It then applies a regular expression to check the number. This regex validates against standard North American Numbering Plan formats and even allows for an optional leading "1". It also rejects invalid area code and prefix combinations, according to one source.

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

A Custom Rule for Ten Digits

If you only need to confirm the input contains exactly ten digits, a custom validation rule is a direct approach. You can define a new method with "$.validator.addMethod" that first normalizes the input.

This process involves the removal of all non-digit characters. After cleanup, the rule uses a simple regular expression, "/^\d{10}$/", to test if the remaining string is exactly ten digits long. This method supports flexible inputs like "(415)-555-0134" while the final test is against the sanitized string, as detailed on Stack Overflow.

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

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

HTML5 Constraint Validation with jQuery

This method relies on the browser's built-in validation features, with jQuery employed to trigger the check. You configure an input field with specific HTML5 attributes to enforce a format.

The `type="tel"` attribute signals to mobile devices that they should display a numeric keypad. However, it adds no validation itself. The "pattern" attribute is mandatory for validation, where you specify a regular expression like "\d{3}-\d{3}-\d{4}". On form submission, jQuery can call the `checkValidity()` method to enforce the rule, as shown in Mozilla's documentation.

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

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

The jQuery Inputmask Plugin

The jQuery Inputmask plugin offers a user-friendly way to guide input. You apply a specific mask, such as "999-999-9999", to an input field. This plugin helps because it blocks non-digit keystrokes and automatically inserts the separators as the user types.

For validation, you check if the field is complete upon form submission through the plugin's "isComplete" helper method. The plugin can also use a built-in "phone" alias for international formats. This approach is detailed on both GitHub and Stack Overflow.

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

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

Challenges of 10-Digit Phone Number Validation

While these jQuery methods appear straightforward, they present significant limitations in real-world applications. Their reliance on fixed patterns and outdated rules often leads to validation failures and poor user experiences.

• Rules like the custom tenDigits method fail internationally. They enforce a strict 10-digit format, which rejects valid numbers under the E.164 standard that allows up to 15 digits and a plus sign, and even some US toll-free formats.
• The phoneUS rule uses a hard-coded list of area codes that quickly becomes obsolete. The North American Numbering Plan constantly evolves with new overlays and re-assigned ranges, so the plugin misclassifies valid numbers over time.
• Solutions like the Inputmask plugin or an HTML5 pattern depend on a fixed visual template. Users who paste numbers with different punctuation or extra spaces break the mask, which makes the validation unreliable without complex pattern permutations.
• All client-side jQuery methods only test a number's superficial shape. Since phone numbers lack a universal checksum, these scripts cannot confirm if a number is active. They might approve a disconnected line or reject a newly ported VoIP number.