XMLHttpRequest (XHR) is an API available to web browser scripting languages such as JavaScript. It is used to send HTTP or HTTPS requests to a web server and load the server response data back into the script. Development versions of all major browsers support URI schemes beyond http: and https:, in particular, blob: URLs are supported.An object of XMLHttpRequest is used for asynchronous communication between client and server.
It performs following operations:
- Sends data from the client in the background
- Receives the data from the server
- Updates the webpage without reloading it.
Properties of XMLHttpRequest object
The common properties of XMLHttpRequest object are as follows:
onReadyStateChange-
It is called whenever readystate attribute changes. It must not be used with synchronous requests.
readyState-
represents the state of the request. It ranges from 0 to 4.
0 UNOPENED open() is not called.
1 OPENED open is called but send() is not called.
2 HEADERS_RECEIVED send() is called, and headers and status are available.
3 LOADING Downloading data; responseText holds the data.
4 DONE The operation is completed fully.
reponseText-
returns response as text.
responseXML-
returns response as XML
Methods of XMLHttpRequest object-
The important methods of XMLHttpRequest object are as follows:
void open(method, URL):
opens the request specifying get or post method and url.
void open(method, URL, async):
same as above but specifies asynchronous or not.
void open(method, URL, async, username, password):
same as above but specifies username and password.
void send():
sends get request.
void send(string):
send post request.
setRequestHeader(header,value):
it adds request headers.
Despite its name, XMLHttpRequest can be used to retrieve any type of data, not just XML, and it supports protocols other than HTTP (including file and ftp).
Create an XMLHttpRequest Object-
To create an instance of XMLHttpRequest, simply do this:
var myRequest = new XMLHttpRequest();
Old versions of Internet Explorer (IE5 and IE6) use an ActiveX Object:
var xmlhttp=new ActiveXObject(“Microsoft.XMLHTTP”);
good explanation dinesh!! will suggest it to my friends..
Thanks Saquib for response.
Dinesh
Hi dinesh,
i comeback to your site for learning EJB3.0 but It is not available in your site.Please post Spring MVC app with EJB .
we learn a lot from your site we really says thanks to you.
Good One
thanks Bhargav!
thanks very good sample source code..
thanks for your views.
If you are using Dao classes it is strongly coupled to the underlying data access framework. In this example, EmployeeDaoImpl extends JdbcDaoSupport and hence it is coupled to JDBC. If this is the case how can we "switch between the aforementioned persistence technologies fairly easily" ?
Please change context root of your application.
In spring.xml, NamedParameterJdbcTemplate should be given a constructor-arg instead of property.
very gooooddddddddddddddddd tutorials
both are fine
i want to make a student management application using spring 3.0 ,how do i start
Have you hands on Spring 3 or you are new for it.
Please explain in details
pics are sexy!
Hi Dinesh plz share the url of RestClient Application. You are taking dynamicWebProject or javaProject. I am trying with javaProject but its giving bellow error. plz help me
Caused by: java.net.ConnectException: Connection refused: connect
please make sure when you ran application your net connection working or not?
ya net connection is good dinesh. first let me conform one thing it is plain javaProject right?
plz share me any prerequirements is needed
Yes Ramesh it is plain java project but in this project we access one web service at plain java project so because of this need net connection.
Are host this web service or web app?
http://localhost:8181/sdnext/doj/webservice/json/employee/
you have download this application at this link
https://www.dineshonjava.com/2013/06/restful-web-services-with-jersey-jax-rs.html#.VAgW11fm6Ph
and deploy to your machine after that you can invoke through that java project application.
ok thank you for replaying Dinesh. your tutorial is very useful. I learn so many things in this tutorial… Great JOB…
Thanks Ramesh!!!
i am new for spring 3
i want to make a student management application using spring 3.0 ,how do i start ,i am new to spring 3
i want to make a student management application using spring 3.0 ,how do i start ,i am new to spring 3
please replay me as early as possible
Hi Rahul,
please start your project whenever you want any help you can contact me.
Thanks, very nice post
if next is failed in one step and still i want to go to next step how to handle that scenario