Sunday, November 18, 2012

basics of JSONP

what is it : It is JSON with some paddind
ex: JSON: {"name","sreenath"}
     JSONP: my({"name","sreenath"})
     in the above 'my ( )' is padding
Why[Usage]: To over come problem of same domain origin policy restriction of AJAX [ you cant make a AJAX call to different domain]. 

How it works:

Its all possible with one condition. < script > tag can access resources in different domain

1.You make request to cross domain resource using script tag passing call back function name.
    < script src="htt://"/>
2. Make your server side code to return passed function with data.
     mycallbackfunc(JSON DATA) ex: mycallbackfunc({"name","sreenath"})
3. implement your call back funcion in your client side code
function   mycallbackfunc(data){
// write your logic here 

That is it you have done cross domain request.

1. You can not make POST request with this
2. server side code needs to be written to return JSONP data