How do you delete an object from a tree in XUL with the delete key?

Question

I'm building a Firefox extension and would like to allow the user to delete objects from the tree with the delete key. I currently call a function when the user presses a button, but would like to allow them to just press the delete key on their keyboard.

Answer 1

Use the key element to define keyboard shortcuts for the window. See tutorial here.

Answer 2

Actually, I figured it out. I added this to the tree element in the XUL:

onkeypress="deleteSelection(event);"

Here is my Javascript:

function deleteSelection(event){
  if(event.keyCode == KeyEvent.DOM_VK_DELETE)
  {   
    var t = document.getElementById('gs-scrapeToolbar-middlePanel-dom-tree');
    if (t.currentIndex > -1) {
      treeView.model.splice(t.currentIndex, 1);
      treeView.treeBox.rowCountChanged(t.currentIndex, -1);
    }
  }
}

Answer 3

I just noticed this when looking at the documentation for nsITreeView:

performAction()

A command API that can be used to invoke commands on the selection. The tree will automatically invoke this method when certain keys are pressed. For example, when the DEL key is pressed, performAction will be called with the delete string.

void performAction(in wstring action);

So I guess that's another way you could accomplish this:

void performAction(action) {
  if (action == 'delete') {
    // delete the thing
  }
}

although I haven't tested it.