phone number patter in html5
<!-- html form tag -->
<form>
<label>Phone Number Format (xxxxxxxxx)</label>
<!-- html input type=tel for phone number which contain a pattern -->
<input type="tel"
name="phone_number"
id="phone_number"
pattern="^\d{10}$"
required="required"
/>
<!-- html input type=submit for submit a form -->
<input type="submit" />
</form>