あいりすミスティリア！だけのウインドウを作る

imys_window.js

/* in about:config
dom.disable_window_open_feature.location = false;
dom.disable_window_open_feature.status = false;
browser.link.open_newwindow.restriction = 1;
*/

// if "location=no" in FireFox, url is in titlebar.
window.open("http://pc-play.games.dmm.com/play/imys/", null, "width=1280,height=720,scrollbars=no,location=yes");
window.open("http://pc-play.games.dmm.co.jp/play/imys_r", null, "width=1280,height=720,scrollbars=no,location=yes");

// in new window's console
// resize consider scaling
window.innerWidth = 1280;
window.innerHeight = 720;
// enter
window.scrollTo(0, 100);

// in ifr's console
{
    let wgl = document.getElementsByClassName("L-webgl_wrapper")[0];
    wgl.style.width = "auto";
    wgl.style.marginLeft = "-25px";
}