Question

In my Firefox Addon’s overlay.xul, can I access it’s DOM in javascript? I can’t figure out how.

Thanks in advance.

Answer 1

An overlay is merged with the DOM of the document that it applies to, it doesn’t have a DOM of its own. So you don’t access the DOM of “the overlay”, you access the DOM of the document that you overlaid. And that is being done the usual way, e.g. via document.getElementById(). You have to consider one thing however: never access the DOM before the document finished loading, this will cause various issues (like other overlays failing to apply). So if your overlay includes a script you can write:

window.addEventListener("load", function() {
  // Window finished loading, now we can do something
  var button = document.getElementById("my-extension-button");
  button.style.backgroundColor = "green";
}, false)