CF5 has added a trick for form validation based on regular expressions that many have missed. If you've ever wanted to validate form input such as email addresses and phone numbers, but have found the built-in validations of CFFORM to be lacking, here's a solution. And you don't need to be a genius with Regular Expressions to start using it.
This tutorial will allow you to enable sitewide error handling with CFERROR. Look like a real professional and display your own custom error page when an error has occurred, instead of the default Cold Fusion page. Not only that, once the error page has been displayed, the details of the error will be automatically emailed to you.
I had had created a login that used cookies to give access to an area of the web
site. The owner of the web site could not login to the area using Windows NT, but upon testing I could always login with my windows 98 system. I could not figure out why the NT system would not login, but I could.
It seemed to be a coding error by the site owner, since other sites could be
logged in to. Some time later I stumbled upon the answer.
This tutorial places the submitted form values into a session, than error checks them. If there is an error it will show the form again with the previous values the user entered pre-entered in the form. It will also tell the user which form fields had errors in them.
This tutorial uses a opt-in mailing list as an example. After the end-user enters their information the information goes to an action page which checks to see if the users email address already exists in the database. If it exists it lets them know and will not enter the duplicate data, if it does not exist it enters them into the mailing list.