There are a few situations where it might be benficial to disable input controls on a form. You can enable and disable elements on a page dynamically with jQuery by setting their attributes accordingly.
//attr(attributeName, value);
//this is equivalent to <some_tag disabled="disabled" ...>
$('.creditCard').attr('disabled', 'disabled');
To re-enable the element, the removeAttr() method should be used. This will completely remove the disabled attribute from the element instead of just blanking it out.
$('.creditCard').removeAttr('disabled');
This adds another tool to help improve the overall user experience and reduce the chances for input error.