<input type="tel" id="ph_no" name="ph_no" placeholder="" pattern="^(+91)?[6-9]\d{9}$" required> not working code example

Example: how to validate mobile number in html form

<div>
  <label for="phone">Enter your phone number:</label>
<input type="tel" id="phone" name="phone"  pattern="+94[7-9]{2}-[0-9]{3}-[0-9]{4}" value="+94">
 </div>