Validating username and password in servlet
However, prior to April 2006, XMLHttp Request was implemented differently across browsers.
For example, Internet Explorer 6 implements XMLHttp Request as an Active X object.
In Ajax, the XMLHttp Request object is what provides the asynchronous communication between Web applications and underlying servers and business services.
With the XMLHttp Request object, clients may retrieve and submit XML data directly to the Web server without reloading the page.
Thus, a complete form does not have to be posted to the server to check if data in the form is valid.
In this article, you'll learn how to create a Web application using Ajax in Oracle JDeveloper 10 (10.1.3). As a J2EE developer, you're probably familiar with DOM and Java Script, but not necessarily so with XMLHttp Request.
Sends a HTTP request to the server and receives a response.
3-Some data has been received, but invoking the response XML produces null, because response headers and status are not completely available. Invoking the open() method sets the ready State property to 1.
response Text, response XML, status, and status Text properties are set to their initial values.
The different values of ready State are: 0-XMLHttp Request object has been created, but not initialized. 1-The object has been created and initialized, but the send() method has not been called.
2-The send() method has been called, but the status and headers are not available. Opens a HTTP request, but does not send the request.Without Ajax, the validity of data in the form is not checked until the form is submitted.