Verifies the current keystroke event before the data is committed. It can be used to check target form field values to verify, for example, whether character data was entered instead of numeric data. JavaScript sets this property to true after the last keystroke event and before the field is validated.
Target Platforms: .NET9; .NET 8; .NET 7; .NET 6; .NET Framework 4.8, 4.7, 4.6, 4.5, 4.0, 3.5