When presenting your users with a form to enter information, you want to ensure that the values they enter are in the correct format. For example, if you ask a user to enter his or her zip code and they enter "Bob," you don't want to let them continue until they fix the entry and enter a ZIP code in the correct format. The process (or art) of ensuring that all form fields comply to a certain format is known as form validation.
Server-side form validation differs from client-side form validation in that it does not occur until the form is submitted back to the Web server. When it is, at that point the form values are checked to ensure that the are valid. If they are, the script can continue processing. If the form values are invalid, however, the script must send the user an error message and take them back to the form to let them correct their invalid entries.
FAQ posted by Scott Mitchell at
10/6/2000 7:50:01 PM to the
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