function handleEnter (field, event) {  
        var keyCode = event.keyCode ? event.keyCode : event.which ? event.which : event.charCode;  
        if (keyCode == 13) {  
            var i;  
            for (i = 0; i < field.form.elements.length; i++)  
                if (field == field.form.elements[i])  
                    break;  
            i = (i + 1) % field.form.elements.length;  
            field.form.elements[i].focus();  
            return false;  
        }   
        else  
          return true;  
}