E cart 6 international phone number

Hi I have a site I built using cart 6. We have been getting a lot of international clients lately, they are having trouble checking out with the phone number validation. It is set to X (xxx)(xxx)(xxxx). I would like to make it required but, clients to be able to enter there country"s phone number. Current code for input looks like this


<div class="col-xs-12 col-sm-6 col-md-6">
<div class="form-group control-group">
<label for="Phone_Number" class="sublabel" > Phone:<span class="text-danger">&nbsp;*</span></label>
<input id="Phone_Number" name="Phone_Number" type="text" value="<?php echo(WA_coalesce(array($users->getColumnVal("UserPhone"),(isset($_GET["invalid"])?ValidatedField("confirmcart","Phone_Number"):"")))); ?>" class="form-control" tabindex="5" pattern="\(\d{3}\) \d{3}[\-]\d{4}" title="Please enter a 10 digit phone number" required="true" onBlur="WAValidatePN(document.getElementById('CheckoutWizard_NewFromBlank_Default').Phone_Number,'',false,true,'x (xxx) xxx-xxxx',document.getElementById('CheckoutWizard_NewFromBlank_Default').Phone_Number,0,true);">
<?php
if (ValidatedField('confirmcart','confirmcart')) {
if ((strpos((",".ValidatedField("confirmcart","confirmcart").","), "," . "4" . ",") !== false || "4" == "")) {
if (!(false)) {
?>
<span class="serverInvalidState" id="Phone_Number_ServerError">Please enter a least 10 digit phone number</span>
<?php //WAFV_Conditional confirm_cart.php confirmcart(4:)
}
}
}?>

</div>
</div>