phone number validation in magento 1.9.2 - validation

Question

i have add class "validate-phoneStrict" with phone number input but still i am able to add alphabets in phone number field.
what i have to do to solve problem?
<input type="text" name="billing[telephone]"
value="<?php echo $this->escapeHtml($this->getAddress()->getTelephone()) ?>" title="<?php echo $this->__('Telephone') ?>" class="input-text validate-phoneStrict <?php echo $this->helper('customer/address')->getAttributeValidationClass('telephone') ?> "
id="billing:telephone" />

Answer 1

You should have to wrote the java script function to do the phone number validation
<input type="text" name="billing[telephone]" value="<?php echo $this->escapeHtml($this->getAddress()->getTelephone()) ?>" title="<?php echo $this->__('Telephone') ?>" class="input-text <?php echo $this->helper('customer/address')->getAttributeValidationClass('telephone') ?> validate-mobileno" id="billing:telephone" placeholder="Mobile"/>
<script type="text/javascript">
//<![CDATA[
if(Validation) {
Validation.addAllThese([
['validate-mobileno','Enter correct mobile number (Eg:919986858483)',
function(v){
var timePat ="^((\+){0,1}91(\s){0,1}(\-){0,1}(\s){0,1}){0,1}9[0-9](\s){0,1}(\-){0,1}(\s){0,1}[1-9]{1}[0-9]{7}$";
// var matchArray = v.match(timePat);
if(v.length > 0){
if(v.length !=12){
return false;
}else if(v[0] != 9 || v[1] != 1 ){
return false;
}else if(v[2]!=9 && v[2]!=8 && v[2]!=7){
return false;
}
return true;
}else {
return false;
}
}
]])};
var dataForm = new VarienForm('form-validate', true);
//]]>
</script>