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Validating text box entries

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Where possible, require user confirmation for irreversible actions, such as permanent deletion of data.Examples include: These tutorials provide best-practice guidance on implementing accessibility in different situations.

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Instead, it will display a message that is generated by the web browser itself.Note that the label also displays “(required)”, to inform users that don’t use assistive technology or use older web browsers that do not support the HTML5 attribute informs assistive technologies about required controls so that they are appropriately announced to the users (as opposed to validating the input).Most current web browsers automatically set its value to .In some situations, such as validating custom controls or supporting legacy browsers, additional scripting may be necessary to validate user input.Custom validation needs to notify users in an accessible way as described in the User Notifications part of this tutorial.Client-side validation alone does not ensure security; therefore data needs to be validated on the server-side as well.

Forms frequently include required input that needs to be clearly identified using labels.

For example, telephone numbers are written with different separators and digit groupings.

Your form will be easier to use if it can interpret multiple notations. For example, postal codes aren't confined to just numbers in some countries, so using an can easily become a problem for many of your website users.

The first project is a class library called "Reg Ex Controls" which contains a class called "Reg Ex Text Box"; this class is an extended text box control that provides the means to store a regular expression and to test the text box text against the regular expression.

The second project is a test windows form application called "Test Reg Ex Controls"; this project contains a single windows form that shows five examples of the extended text box control in use in conjunction with an error control.

This is particularly important for actions that are permanent or otherwise critical, but also when data cannot be automatically checked.