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Does anyone have a creative solution that allows me to hide menu items from a web page embedded in my web page?

I fear that the answer will be "Impossible due to browser security policy" but I really need to accomplish the following:
The problem I have is that the content to be embedded in my web page includes some menu items that I need to remove/hide because they trigger operations that I need to prevent. I cannot find a way to address these DOM nodes to hide them.
I have a web page and need to embed a URL from another domain into my web page. I have tried this with and also by using Ajax to fetch the URL contents and insert them into the DOM of my web page. These two methods have different results.
If I use to embed the page from the "foreign" domain I can see the "foreign" domain's content and I can address the node but all attempts to access the nodes underneath return null. There is no error message (in Firefox) but I suspect that I am getting null because the browser is enforcing the same-domain policy.
On the other hand, if I use Ajax to insert the page content into my web page I don't even see the content and in this case there is a CORS error in the Firefox debugger console.
Since I don't control the "foreign" domain I can't modify it to use the window.postMessage(); technique.
Can anyone suggest a way for me to be able to hide menu items that are in content fetched from a "foreign" domain? (Gotta be a way, gotta be a way, ...)
Thank you.

New JavaScript window in HTML element

I know in JavaScript you can use the window.open() to open a new window in a browser.
Is it possible to create a new window in an HTML element. So instead of creating an iframe it creates a browser or window in the HTML.
Why not use an iframe?
Cross domain policy, iframes can't display all websites
Background:
I am trying to add in a website browser to a game, this game allows modding of the ui which uses CoherentUI(Essentially the UI is HTML)

The only thing you could do is some "readfile" script in php or any Server side language, open the Website on your own, read and parse the whole content, rewrite links if needed, ... and echo it in some div. If you want it live and in-game you should use Ajax and jquery for example.
But i guess, you should not do this without permission of the Website owner, as you copy and use his content without mentioning a source.

Improving the Bookmarklet Experience - Though Hacking?

So I have a site specific bookmarklet that create a page with a toolbar (using localstorage to set/get variables) and then creates an iframe for a destination site, say www.example.com. [Idea heavily borrowed from the wonderful RWD Bookmarklet (http://responsive.victorcoulon.fr/) ]. It works great, but I wanted to provide that a clickable link to that bookmarklet (because it is a pain to add a bookmarklet in an Ipad) but unfortunately that results in the obvious XSS cross-site problems since the link does not reside within www.example.com.
To improve this experience I was wondering if it would be possible to do have a popup (like twitter's) which would exploit an existing generic loadScript function currently present on www.example.com. From within the javascript console on www.example.com I currently can invoke a supervar.loadScript("http://dl.dropboxusercontent.com/s/blah/thefile.js") and it works. Which means I do not need to append or cross load the js into the iframe but I would need the iframe itself to invoke the supervar.loadScript call.
It is possible to invoke the supervar.loadScript on say a window.onload/document.ready type scenario or would the context of the popup code be pointing to about:blank/notexample.com in which case the supervar would not exist. Could window.postMessage be of any use?
UPDATE: Clarification
I am trying to have a button which would contain javascript code that in turn would open a new window/tab to a site but would be able to invoke a command on a variable that will be present when the DOM is ready.
Again, I'm quite new to XSS so I'm not sure if this is a security problem on the site. I'm not trying to access variables from one site to the next, just a means to load a userscript on a site without having to use a bookmarklet.
For a real test:
Visit: firsttaste.kraftcanada.com.
Open the javascript console and then enter: nitroWidget.loadScript("https://dl.dropboxusercontent.com/s/fcfbpfdmzrxywh9/mwolfe_alert.js")
This will execute the mwolfe_alert.js which merely contains an alert message.
Is there a way that I could create a clickable link on a site outside of *.kraftcanada.com which would create a popup/new tab that upon the {document,window,$}.onload/read would invoke the nitroWidget.loadScript?

URL tracking functionality

I want my webpage to have two parts. The top part has a textbox. When the user types a URL into the textbox, the bottom part browses to the content of that URL. When the user clicks a link within the bottom part, the bottom part navigates to the new URL, and the textbox in the top part changes to the new URL. How can I do it?
NOTE: This behavior is the same as in Google Translate (e.g. here), but without any translation.

first problem..
Same origin issue
The only way to achieve what you are asking is exactly the way google translate does what it does - which is to use a server-side powered script as a proxy request:
http://translate.google.com/translate_un?depth=1&hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=auto&tl=en&twu=1&u=http://de.wikipedia.org/wiki/USA&lang=de&usg=ALkJrhgoLkbUGvOPUCHoNZIkVcMQpXhxZg
The above is the URL taken from the iframe that Google translate uses to display the translated page. The main thing to note is that the domain part of the URL is the same as the parent page's URL http://translate.google.com -- if both your frame and your parent window do not share the same domain, then your parent window's JavaScript wont be able to access anything within the iframe. It will be blocked by your browser's in-built security.
Obviously the above wont be a problem if in your project you are only ever going to be navigating your own pages (on the same domain), but considering you are proffering Google Translate as an example I'm assuming not.
What would Google do?
What the above URL does is to ask the server-side to fetch the wikipedia page and return it so that the iframe can display it - but to the iframe this page appears to be hosted on translate.google.com rather than wikipedia. This means that the iframe stays within the same origin as the parent window, and means that JavaScript can be used to edit or modify the page within the iframe.
next problem....
Rewrite the proxied content
Basically what I'm saying is that this can't be achieved with just HTML and client-side JavaScript - you need to have something to help from the server-side i.e. PHP, Python, Ruby, Lisp, Node.. and so on. This script will be responsible for making sure the proxied page appears/renders correctly e.g. you will have to make sure relative links to content/images/css on the original server are not broken (you can use the base tag or physically rewrite relative links). There are also many sites that would see this as an illegal use of their site, as per their site's terms of use and so should be black listed from your service.
final problem..?
Prevent the user from breaking away from your proxy
Once you have your proxy script, you can then use an iframe (please avoid using old framesets), and a bit of JavaScript magic that onload or ondomready of the iframe rewrites all of the links, forms and buttons in the page. This is so that when clicked or submitted, they post to your proxy script rather than the original destination. This rewrite code would also have to send the original destination to your proxy script some how - like u in the Google translate URL. Once you've sorted this, it will mean your iframe will reload with the new destination content, but - all importantly - your iframe will stay on the same domain.
too many problems!
If it were me, personally, I'd rethink your strategy
Overall this is not a simple task, and it isn't 100% fullproof either because there are many things that will cause problems:
Certain sites are designed to break out of frames.
There are ways a user can navigate from a page that can not be easily rewritten i.e. any navigation powered by JavaScript.
Certain pages are designed to break when served up from the wrong host.
Sites that do this kind of 'proxying' of other websites can get into hot water with regards to copyright and usage.
The reason why Google can do it is because they have a lot of time, money and resources... oh and a great deal of what Google translate does is actually handled on the server-side - not in JavaScript.
suggestions
If you are looking for tracking users navigating through your own site:
Use Google Analytics.
Or implement a simple server-side tracking system using cookies.
If you are looking to track users coming to your site and then travelling on to the rest of the world wide web:
Give up, web technologies are designed to prevent things like this.
Or join an online marketing company, they do their best to get around the prevention of things like this.

add a javascript function to your second frame -
<frame id="dataframe" src="frame_a.htm" onload="load()">
let the text box have an id - say "test"
function load()
{
document.getElementById('test').value=document.getElementById('dataframe').src
}

Javascript iFrame Limitations

I know that, for security reasons, javascript can't read the contents of an iframe if it belongs to a different domain. This makes sense, given that the entire page could be an iframe with snooping scripts outside of the frame.
The question is - are there equal limitations in the other direction? Can javascript within an iframe (from a different domain) read and manipulate the dom in its parent window?
Thanks!

You can't.
This would be a security hole. Now that everyone is crazy adding facebook iframes to their sites, imagine if javascript from FB could interact with your page ;)
Anyway, i set up a small example, and got the same origin warning when i tried to get a parent's div from inside the iframe (which was in another domain)

If you want to use this in a two domains that you own (not trying to attack anyone) you can do that using ajax as described Here.