The System.Web.UI.WebControls.RegularExpressionValidator control checks whether the value of an input control matches a pattern defined by a regular expression. This type of validation allows you to check for predictable sequences of characters, such as those in e-mail addresses, telephone numbers, and postal codes.

Both server-side and client-side validation are performed unless the browser does not support client-side validation or client-side validation is explicitly disabled (by setting the BaseValidator.EnableClientScript property to false).

The regular-expression validation implementation is slightly different on the client than on the server. On the client, JScript regular-expression syntax is used. On the server, System.Text.RegularExpressions.Regex syntax is used. Since JScript regular expression syntax is a subset of System.Text.RegularExpressions.Regex syntax, it is recommended that JScript regular-expression syntax be used in order to yield the same results on both the client and the server.

For additional information about validation controls, see System.Web.UI.WebControls.BaseValidator. For more information on regular expressions, see .NET Framework Regular Expressions.

Accessibility

For information about how to configure this control so that it generates markup that conforms to accessibility standards, see Accessibility in Visual Studio 2010 and ASP.NET 4 and ASP.NET Controls and Accessibility.