Doc Shell Swapping Example - firefox-addon

Question

I'm trying to write a simple example to show docshell swapping from one iframe to another.
I wrote this, can run from scratchpad with environment browser:
var doc = gBrowser.contentDocument;
var iframeA = doc.createElement('iframe');
iframeA.setAttribute('id', 'a');
iframeA.setAttribute('src', 'http://www.bing.com');
doc.documentElement.appendChild(iframeA);
var iframeB = doc.createElement('iframe');
iframeB.setAttribute('id', 'b');
iframeB.setAttribute('src', 'data:text/html,swap to here');
doc.documentElement.appendChild(iframeB);
doc.defaultView.setTimeout(function() {
var srcFrame = iframeA;
var targetFrame = iframeB;
doc.defaultView.alert('will swap now');
srcFrame.QueryInterface(Ci.nsIFrameLoaderOwner).swapFrameLoaders(targetFrame)
doc.defaultView.alert('swap done');
}, 5000)
However this throws this error when it tries to swap:
/*
TypeError: Argument 1 of HTMLIFrameElement.swapFrameLoaders does not implement interface XULElement. Scratchpad/1:17
*/
Any ideas on how to fix?
Thanks

Answer 1

Thanks to #mook and #mossop from irc #extdev for the help.
The reason it didnt work was because:
pretty sure it needs to be a
Looks like gBrowser.contentDocument might be a html page? You must be using XUL elements
No idea if it even works in content either - I think it doesn't
and the things to be swapped must either both be type=content or neither can be, or something like that (translation: the type attribute of both source and target must be the same. so if one is content-primary the other must be content-primary as well)
This works:
var doc = document; //gBrowser.contentDocument;
var iframeA = doc.createElementNS('http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul', 'browser');
iframeA.setAttribute('id', 'a');
iframeA.setAttribute('src', 'http://www.bing.com');
iframeA.setAttribute('style', 'height:100px;');
doc.documentElement.appendChild(iframeA);
var iframeB = doc.createElementNS('http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul', 'browser');
iframeB.setAttribute('id', 'b');
iframeB.setAttribute('src', 'data:text/html,swap to here');
iframeB.setAttribute('style', 'height:100px;');
doc.documentElement.appendChild(iframeB);
doc.defaultView.setTimeout(function() {
var srcFrame = iframeA;
var targetFrame = iframeB;
doc.defaultView.alert('will swap now');
srcFrame.QueryInterface(Ci.nsIFrameLoaderOwner).swapFrameLoaders(targetFrame)
doc.defaultView.alert('swap done');
}, 5000)
so in other words even if you made iframe with xul namespace it would not swap if you put it in an html document. like this example here:
var xulDoc = document;
var doc = gBrowser.contentDocument;
var iframeA = xulDoc.createElementNS('http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul', 'iframe');
iframeA.setAttribute('id', 'a');
iframeA.setAttribute('src', 'http://www.bing.com');
iframeA.setAttribute('type', 'content');
iframeA.setAttribute('style', 'height:100px;width:100px;');
doc.documentElement.appendChild(iframeA);
var iframeB = xulDoc.createElementNS('http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul', 'iframe');
iframeB.setAttribute('id', 'b');
iframeB.setAttribute('src', 'data:text/html,swap to here');
iframeB.setAttribute('type', 'content');
iframeB.setAttribute('style', 'height:100px;width:100px;');
doc.documentElement.appendChild(iframeB);
doc.defaultView.setTimeout(function() {
var srcFrame = iframeA;
var targetFrame = iframeB;
doc.defaultView.alert('will swap now');
srcFrame.QueryInterface(Ci.nsIFrameLoaderOwner).swapFrameLoaders(targetFrame)
doc.defaultView.alert('swap done');
}, 5000)
It throws:
NS_ERROR_NOT_IMPLEMENTED: Scratchpad/2:21
this line is the swapFrameLoaders line
so its recommended to not use iframe with xul namespace as if you do you wont get the DOMContentLoaded and some other events http://forums.mozillazine.org/viewtopic.php?f=19&t=2809781&hilit=iframe+html+namespace
so its recommended to use element