AJAX and cross-domain/site request:
when the downloaded html on client is from different server than the AJAX xmlHttpRequest is going to---this is called
You can get error --- No 'Access-Control-Allow-Origin' header is present on the requested resource
from http://stackoverflow.com/questions/20035101/no-access-control-allow-origin-header-is-present-on-the-requested-resource
SOLUTION 0
You are doing an XMLHttpRequest to a different domain than your page is on. So the browser is blocking it as it usually allows a request in the same origin for security reasons.
NOTE: Regular web pages can use the XMLHttpRequest object to send and receive data from remote servers, but they're limited by the same origin policy. Extensions aren't so limited. An extension can talk to remote servers outside of its origin, as long as it first requests cross-origin permissions.
The easy way is to just add the extension in google chrome to allow access using CORS.
Just enable this extension whenever you want allow access to no 'access-control-allow-origin'header request.
SOLUTION 1
You are doing an XMLHttpRequest to a different domain than your page is on. So the browser is blocking it as it usually allows a request in the same origin for security reasons. You need to do something different when you want to do a cross-domain request. A tutorial about how to achieve that is Using CORS.
When you are using postman they are not restricted by this policy. Quoted from Cross-Origin XMLHttpRequest:
Regular web pages can use the XMLHttpRequest object to send and receive data from remote servers, but they're limited by the same origin policy. Extensions aren't so limited. An extension can talk to remote servers outside of its origin, as long as it first requests cross-origin permissions.
SOLUTION 2
he browser is not blocking the request. The only browsers that outright block cross-origin ajax requests is IE7 or older. All browsers, other than IE7 and older, implement the CORS spec (IE8 & IE9 partially). All you need to do is opt-in to CORS requests on your API server by returning the proper headers based on the request. You should read up on CORS concepts at mzl.la/VOFrSz. Postman sends requests via XHR as well. If you are not seeing the same problem when using postman, this means that you are unknowingly not sending the same request via postman