function reg(elmnt) {
                        
    if (elmnt.previousSibling.previousSibling.value == elmnt.previousSibling.previousSibling.defaultValue || elmnt.previousSibling.previousSibling.value == '') {
        //document.giftcard.previousSibling.previousSibling.innerHTML = 'Please enter your unique card number';
        $.prompt('Please enter your unique card number',{top:'30%',callback:function() {
              elmnt.previousSibling.previousSibling.focus();
              
        }});
        return false;
    
    } else if (parseInt(elmnt.previousSibling.previousSibling.value) && elmnt.previousSibling.previousSibling.value.length == 4) {
        elmnt.parentNode.submit();
    } else {
        $.prompt('Please enter your unique card number',{top:'30%',callback:function() {
        elmnt.previousSibling.previousSibling.focus();
        }});
    }

}