2.2.GA\bin directory. Invoke the userregistration.jsp
with the URL http://localhost:8080/webapp1/
userregistration.jsp. Start to specify a User Id value. The User
Id value gets modified with each modification to the User Id field and a
validation message gets displayed as shown in Fig 5.7. Single-character
user IDs are not typically used. The business logic of what is and what is
not a valid user ID can be specified on the server side. In addition to
testing if a user ID entry has been already specified in the database
business logic can be added to check the length of the user ID and whether
or not it starts with a particular character.
5.4 Deploying and Running the DWR Application 105
Fig. 5.7 Validating User Id
If a valid User Id is specified validation message ???User Id is Valid???
gets displayed. If a User Id that is already defined in the database is
specified a validation message ???User Id is not Valid??? gets displayed as
shown in Fig. 5.8.
Fig. 5.8 Non Valid User Id
To create a new user registration specify a valid User Id, specify a
password and click on the Submit button as shown in Fig. 5.9.
106 5 Ajax with Java-DWR
Fig. 5.9 Creating a new User Registration
A user entry gets created and the form fields get reset. If the same user
Id is re-specified a validation message indicating that the User Id is not
valid gets displayed.
5.5 Summary
Ajax is a JavaScript based web technique.
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