Also provides interfaces to handle
events generated by the widgets. For example,
the ClickListener is registered with widgets
generating a click event such as a button. The
FormHandler interface handles form submit
events.
com.google.gwt.xml.client Provides classes and interfaces for generating
and parsing XML documents. The XMLParser
class is used to create and parse an XML
document. The Document interface represents a
document node and Element interface represents
an element node.
4.5 Creating a Form Validation Ajax Application 77
4.5 Creating a Form Validation Ajax Application
In this section we shall modify the example GWT application to create a
Catalog Form that is used to create a catalog entry in a HashMap. The
Catalog form consists of input fields CatalogID, Journal, Publisher,
Edition, Title, Author and Ajax is used for dynamic validation of the
CatalogID field.
First, we need to modify the host HTML page, C:\GWT\gwt-windows-
1.4.60\src\com\gwt\public\CatalogForm.html, to add DOM elements for
labels and input text boxes to the HTML table. Add a button to submit the
table and a DOM element for the validation message for the Catalog ID
field. If a new Catalog ID is already in the HashMap, a validation
message, ???Catalog Id is not Valid???, gets displayed, the text fields get filled
with element values for the specified Catalog Id and the submit button gets
disabled.
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