client side validate phone number and change error message
in html5 input tag
<input type="tel" pattern="^(?:\+?(61))? ?(?:\((?=.*\)))?(0?[2-57-8])\)? ?(\d\d(?:[- ](?=\d{3})|(?!\d\d[- ]?\d[- ]))\d\d[- ]?\d[- ]?\d{3})$" name="phone" class="name validationname" placeholder="PHONE *" oninvalid="setCustomValidity('Please enter a valid phone number.')" onchange="try{setCustomValidity('')}catch(e){}" required />