Dojo: Using the Dojo JavaScript Library to Build Ajax Applications

2

Using Dojo for Client-sideValidation

To err is human...

—Alexander Pope (1688–1744)

We all make mistakes, so input forms must anticipate that users will inadvertently enter bad data. Identifying and correcting these mistakes is an important job of an HTML form, and this chapter describes Dojo features that allow you to easily add validation.

2.1. Validating Form Fields

Validating input data on web pages is usually a function performed by the server. The web page allows the user to enter data, and when the Submit button is pressed, the browser wraps up the data into an HTTP request and sends it to the server. The server checks each data field to make sure it is valid, and if any problems are found, a new form along with error messages is sent ...