Filtered TextBox Extender in ASP.NET Ajax example

FilteredTextBox is an extender which prevents a user from entering invalid characters into a text box. Note that since this effect can be avoided by deactivating JavaScript, you should use this extender as a convenience for your users, but you must never expect that the data being sent to the server consists of "valid" chars only.

Output for below Code :
//Enter UpperCase Letters
//Enter LowerCase Letters
//Enter Numeric Digits
//Enter Custom Valid Characters
//Enter Custom InvalidChar Letters

.aspx Page
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