Ajax doubt - url in open method

[omkar patkar]

Hello friends,

I have a doubt in ajax. Can i give a complete url in the open method of the XMLHttpRequest object ? like for example: -

 
var url = "http://www.google.com";
 
xmlHttpObj.open( "GET", url, true );
 

I tried to debug this using the firebug plug-in in Firefox. I am using Firefox 3.0.5. While debugging, after the request is sent, the script pane of the debugger loads with a page related to google, but the screen does not show anything related to google.

In IE, unfortunately there is no debugger to go line by line, but the result is the same as Firefox - nothing happens !!!

Can some one please help me with the problem?

[Eric Pascarello]

Scroll to the Security Section in this article: http://developer.apple.com/internet/webcontent/xmlhttpreq.html

That will tel you why it does not work.

Eric

[omkar patkar]

Thank you so much Eric. Now i understand that, cross domain access is not possible. Which also means that, the responseText can never contain, a response given by a resource from some other domain.

But i have another doubt related to this,

What if the there is a need to access third party application to show updates about something at regular intervals on a part of page without refresh...like for example ... news ? or weather? or cricket/football match score? How can this be achieved in such a scenario?

Another doubt, let's say i have hosted two web applications on abc.com as app1 and app2.

If i want to access app1 i will hit the url as : -
http://abc.com/app1/home.htm

if i want to access app2 i will hit the url as : -
http://abc.com/app2/welcome.htm

in such an environment, can i access app2 from app1 using Ajax, as their domains are same that is "localhost" ?

For example, in Ajax script of home.htm of app1 if i write,

xmlHttpObj.open("GET", "http://abc.com/app2/welcome.htm", true);

is that allowed in AJAX? Million thanks in advance

[Eric Pascarello]

You can access any files on the same domain, but sub domains are seen as different domains

so if the address bar reads http://example.com/blue/house.html

Good:

http://example.com/hey

http://example.com/foo

http://example.com/bar/brain/candy

bad:

http://sub1.example.com/hey

http://example123.com/

http://an.example.com/blue/house.html

If you want to access a 3rd party site you either need to use a proxy on your server or you can use a JSON request if they offer a JSON Web Service. Here is an example of mine that calls a yahoo webservice with JavaScript http://www.pascarello.com/examples/JsonYahooExample.html

Eric

[omkar patkar]

Thanks for all the info Eric. I am learning AJAX. I don't know how JSON works, so i did not understand the JSON example. But i got your point. Thanks ! Don't mind if i ask you more doubts, when i start learning JSON ... he he he!

... thanks and Merry Xmas and a Happy new Year!!! to all java ranchers!!!