附加组件栏

// Find the most recently used window

var mediator = Components.classes[
  "@mozilla.org/appshell/window-mediator;1"
].getService(Components.interfaces.nsIWindowMediator);
var doc = mediator.getMostRecentWindow("navigator:browser").document;

// Get the add-on bar for that window

var addonBar = doc.getElementById("addon-bar");

// Construct the new toolbar item

var newItem = doc.createElement("toolbaritem");
var itemLabel = doc.createElement("label");

// Add the item to the toolbar and set its text label

newItem.appendChild(itemLabel);
addonBar.appendChild(newItem);
itemLabel.value = "Hello world!";

var firstRun = Services.prefs.getBoolPref("extensions.YOUREXT.firstRun");

var curVersion = "0.0.0";

if (firstRun) {
  Services.prefs.setBoolPref("extensions.YOUREXT.firstRun", false);
  Services.prefs.setCharPref("extensions.YOUREXT.installedVersion", curVersion);
  /* Code related to firstRun */
} else {
  try {
    var installedVersion = Services.prefs.getCharPref(
      "extensions.YOUREXT.installedVersion",
    );
    if (curVersion > installedVersion) {
      Services.prefs.setCharPref(
        "extensions.YOUREXT.installedVersion",
        curVersion,
      );
      /* Code related to upgrade */
    }
  } catch (ex) {
    /* Code related to a reinstall */
  }
}