Client-side validation provides validation within the browser on client computers through Java Script.Because the code is stored within the page or within a linked file, it is downloaded into the browser when a user accesses the page and, therefore, doesn't require a roundtrip to the server.Both Java Script and JScript are ECMAScript-compliant languages.When referring to Java Script in general, this article uses the generally accepted term "Java Script." However, when referring to documentation on the Microsoft Developer Network (MSDN) Web site, this article uses the term "JScript." Note The previous code specifies an e-mail address for the Action attribute of the form property.
Lisa Wollin Microsoft Corporation May 2004 Applies to: Microsoft® Office Front Page® 2003 Microsoft Front Page 2002 Microsoft Front Page 2000 Summary: Learn how validate HTML form fields using Java Script in Microsoft Office Front Page 2003.However, for some form functions, server-side validation is necessary.For example, if you have a form that populates a drop-down list based on the value of another form field, server-side processing may be needed to pull data from a database and populate the drop-down list.A user may have a browser that doesn't support client-side scripting or may have scripting disabled in the browser.
Knowing the limits of client-side scripting helps you decide whether to use client-side form validation.
For example, you may want to ensure that someone inserts a valid e-mail address into a text box, or perhaps you want to ensure that someone fills in certain fields.