Is it possible to inject JavaScript code in a page embedded by IFRAME tag?

There 开发者_JAVA技巧is a certain page (say, named "TargetPage.html" in which I inject the Javascript code below by means of a Firefox extension:

<!-- TargetPage.html -->
unsafeWindow.document.getElementById("target-element").click();

I want to embed this page into another page (say, named "AnotherPage.php") by using the HTML tag "iframe". Like below:

<!-- AnotherPage.php -->
<iframe src="TargetPage.html"></iframe>

Now that I embedded it via "iframe", there is no way to inject any JavaScript code with a browser extension.

Is there any way of running this code in the embedded page?

Only if both pages are in the same domain.

Otherwise is considered cross-domain scripts, and it's a big no-no, for browsers to allow it.

However, there are ways to achieve such communication between domains.