You’re trying to do cross origin resource sharing (CORS). The bad news is that without a server as a middle man there is no way to do this on a normal web page. The good news is that in a chrome extension you can request permission to access any url’s you want. Just put something like this in your manifest.json file.
Allow connections to your site:
"permissions": [
"http://*.radionsm.lv/"
],
Allow connections to any site:
"permissions": [
"http://*/"
],
When the user installs your extension chrome will inform them of the permissions required in a dialogue box prior to the completion of the install.