study.js

study.js

this.Study = {
  onPageLoad: evt => {
    console.log("caught pageload event", evt);
    console.log("stuff is:", stuff);
  },  

  init() {
    this.stuff = "things";
    this.win = Services.wm.getMostRecentWindow("navigator:browser");
    this.win.gBrowser.addEventListener("DOMContentLoaded", this.onPageLoad);
  },  
  
  uninit() {
    this.win.gBrowser.removeEventListener("DOMContentLoaded", this.onPageLoad);
  }
}   

Study.init();