The reason that you did not got any exception :
Most browsers don't support multiple popups so in order to accomplish it wou need to try using:
window.open(yoururl,"_blank",'PopUp',randomnumber,'scrollbars=1,menubar=0,resizable=1,width=850,height=500');
Or Give each window a new window name.
window.open(url, WindowName)
Security Risk
You can't add an event listner with different origin using JavaScript, it would be a huge security flaw if you could do it. For the same-origin policy browsers block scripts trying to access a frame with a different origin.  
Origin is considered different if at least one of the following parts of the address isn't maintained: 
<protocol>://<hostname>:<port>/...
Protocol, hostname and port must be the same of your domain, if you want to access a frame. 
Examples
Here's what would happen trying to access the following URLs from http://www.example.com/home/index.html 
URL                                             RESULT 
http://www.example.com/home/other.html       -> Success 
http://www.example.com/dir/inner/another.php -> Success 
http://www.example.com:80                    -> Success (default port for HTTP) 
http://www.example.com:2251                  -> Failure: different port 
http://data.example.com/dir/other.html       -> Failure: different hostname 
https://www.example.com/home/index.html:80   -> Failure: different protocol
ftp://www.example.com:21                     -> Failure: different protocol & port 
https://google.com/search?q=james+bond       -> Failure: different protocol, port & hostname 
Not recommended
Disabling same-origin policy in your browser
I'll link the relative answer. However, please remember that disabling the same-origin policy will only affect your browser. Also, running a browser with same-origin security settings disabled grants any website access to cross-origin resources, so it's very unsafe and should NEVER be done if you do not know exactly what you are doing (e.g. development purposes).