Question

I have two subdomains www.example.com and api.example.com. On a page from first domain I open popup window with url api.example.com/some/url and want to use window.opener object to pass data to parent page. But I get error:

Unsafe JavaScript attempt to access frame with URL http://www.example.com/some/page from frame with URL http://api.example.com/some/url. Domains, protocols and ports must match.

Is it possible to fix the issue?

Answer 1

It is possible to pass data between http://www.example.com and api.example.com but not with window.opener. You can set a value in a cookie with Javascript (document.cookie) on the .example.com domain (not http://www.example.com) and it will be readable on http://www.example.com and api.example.com.

On a page from http://www.example.com, if you execute this Javascript:
(source: http://techpatterns.com/downloads/javascript_cookies.php)
then the “somename” cookie will be readable from api.example.com

function Set_Cookie( name, value, expires, path, domain, secure )
{
// set time, it's in milliseconds
var today = new Date();
today.setTime( today.getTime() );

/*
if the expires variable is set, make the correct
expires time, the current script below will set
it for x number of days, to make it for hours,
delete * 24, for minutes, delete * 60 * 24
*/
if ( expires )
{
expires = expires * 1000 * 60 * 60 * 24;
}
var expires_date = new Date( today.getTime() + (expires) );

document.cookie = name + "=" +escape( value ) +
( ( expires ) ? ";expires=" + expires_date.toGMTString() : "" ) +
( ( path ) ? ";path=" + path : "" ) +
( ( domain ) ? ";domain=" + domain : "" ) +
( ( secure ) ? ";secure" : "" );
} 


Set_Cookie("somename", "somevalue", 0, "/", ".example.com");