In the ECMAScript specification, they only exist conceptually: All numbers are always floating point and integers are ranges of numbers without decimal fractions (for details, consult “Integers in Java Script” in “Speaking Java Script”).
(16 printed pages) Introduction Getting Started Writing the Validation Script Connecting the Form to the Script Associating Form Fields with Custom Script Code Listing Conclusion When you create forms, providing form validation is useful to ensure that your customers enter valid and complete data.
(For more information on how to create form validation using the Front Page form feature, see About creating forms in Front Page 2003.) However, if the form validation provided in Front Page does not suit your needs or the site on which you are working is hosted on a server that does not have Front Page Server Extensions from Microsoft installed, you may need to create custom form validation.
Note Front Page Server Extensions are a set of programs that provide access to special Front Page features, such as database processing, form processing, hit counters, and other built-in Front Page components that require server-side processing.
It's still amazing to me that so many sites have no idea how to make a simple form usable.
This article presents methods for validating credit card numbers in a user-friendly fashion.