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As I mentioned at the end of the last video, we can allow communication between a parent frame and

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a child frame, depending upon some settings that we apply to the iFrame element.

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So let me show you another quick diagram again.

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Right now, we have some JavaScript running in the parent frame and some running inside the child frame.

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The current settings of our iFrame allow communication between these two different context.

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So just because the current settings we have, we can very easily and directly communicate between these

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two context.

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But if we change these settings, this communication link can be completely broken and we can isolate

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the iFrame from the parent.

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So let's first take a look at how everything works with our current settings, which are going to allow

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communication.

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All right, so back inside my console, I have once again selected top.

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I'm then going to declare window A equals one once again.

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Well, then change into test HTML now, just as a quick reminder, if I do window A, I get undefined

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because this iFrame element has a different JavaScript execution context.

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So I don't when I reference window, I'm referencing window inside of the iFrame rather than the index

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html file.

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But if I wanted to reference the parent, if I wanted to write some javascript inside of the child and

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somehow get access to the parent, I can write out parent.

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We write out parent inside of the inner iFrame, we can get a reference to the parent window element

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to the parent window object.

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So if I write out parent dot a.

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Now, I see that value of one again right now, because of our current settings, our child iFrame can

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try to access different things inside the parent.

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The opposite is true as well.

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So inside of my test context, I'm going to do window B equals to.

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I'll then go back into my parent context.

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Some top again, if I do window B over here, I get undefined because Window B is a sign inside the

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child, not the parent.

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But if I wanted to somehow reach from the parent into the child, I can write out the following code.

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I can do a document.

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Where is Selecter?

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Or Efraim.

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iFrame, not just frame, that's better, so it's going to give me a reference to that iFrame than to

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reach into the iFrame I can reference content window like so.

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That is going to reach from the parent into the child and get access to that window object, then if

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I try to print out the property on it, there's the number two.

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So that is an example of reaching from the parent into the child and trying to access some different

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properties.

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OK, so at this point time, clearly we are able to kind of reach across this context and kind of make

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changes or get access to properties between the two.

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But this is only because our current settings allow this level of communication.

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So let's take another brief pause, come back to the next video.

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We're going to take a look at some of the different settings we can change to break this communication

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and disallow any communication between the two.