Ограничение ввода символов в поле мобильный телефон - JoomShopping

<div>
          	<label class="name">
            	<?php echo _JSHOP_MOBIL_PHONE ?> <?php if ($config_fields['mobil_phone']['require']){?><span>*</span><?php } ?>
          	</label>
          	<span class="input">
            	<input type="text" name="mobil_phone" id="mobil_phone" value="+380" class="inputbox" />
       		</span></div>

<span class="input">
            	<input type="text" pattern="[0-9]{13}" name="mobil_phone" id="mobil_phone" value="+380" class="inputbox" />
       		</span></div>