ASP.NET by Example

Validating HTML Forms

As an ASP developer working with Classic ASP, one of the most frequent tasks I encountered involved developing HTML forms to gather user inputs, usually for storage in a database of some kind. Often, someone wanted to be able to use this data at some point in the future (though just as often, this was not the case), and when the time came to use the data, the clients invariably wanted the data to be in a clean, consistent format. There are at least a dozen different ways to display a telephone number, for example, but usually only one method was to be used for a particular application.

To accomplish this task with Classic ASP, I learned JavaScript to perform the client-side validation. Early on, I thought that client-side ...