Get the version of an installed Firefox extension

Question

如何获得Firefox扩展的安装版本，例如在“关于”对话框中显示它？

Answer 1

You use the AddonManager API :

Components.utils.import("resource://gre/modules/AddonManager.jsm");
AddonManager.getAddonByID("id@my.addon", function(addon)
{
  alert("Installed version is " + addon.version);
});

Here id@my.addon needs to be replaced by the ID of your add-on of course.