INTERACTIVE WEB SERVICES WITH JAVA

Input Field Validation

- an inevitable part of interactive Web services.

More detailed requirements may be imposed on input fields:

Sometimes, various dependencies between fields are required:

Often, Web programmers are faced with an apparent choice:

client-side validation checks requirements in the browser (using JavaScript)
server-side validation checks requirements on the server (in Java, for instance)

However, both checks must really be performed:

client-side validation gives quick responses, saves bandwidth, and lightens the burden on the server
server-side validation is required since the client may cheat or just not permit JavaScript

This gives the programmer an unpleasant task: