The main problem related to validating mobile numbers in HTML forms is that there is no standard format for mobile numbers. Different countries have different formats for their mobile numbers, making it difficult to create a universal validation rule that works for all countries. Additionally, some countries may require additional information such as area codes or country codes, which can further complicate the validation process. Finally, there are a variety of special characters and symbols used in some mobile number formats which can also make it difficult to create a comprehensive validation rule.
<form> <label for="mobile">Mobile Number:</label><br> <input type="tel" id="mobile" name="mobile" pattern="[0-9]{10}" required><br> <input type="submit"> </form>
1.