How to prevent IFRAME from redirecting top-level window

Try using the onbeforeunload property, which will let the user choose whether he wants to navigate away from the page.

Example: https://developer.mozilla.org/en-US/docs/Web/API/Window.onbeforeunload

In HTML5 you can use sandbox property. Please see Pankrat's answer below. http://www.html5rocks.com/en/tutorials/security/sandboxed-iframes/

I use the sandbox attribute on the iframe element:

• allow-forms allow form submission
• allow-popups allows popups
• allow-pointer-lock allows pointer lock
• allow-same-origin allows the document to maintain its origin
• allow-scripts allows JavaScript execution, and also allows features to trigger automatically
• allow-top-navigation allows the document to break out of the frame by navigating the top-level window

Top navigation is what you want to prevent, so leave that out and it will not be allowed. Anything left out will be blocked

ex.

<iframe sandbox="allow-same-origin allow-scripts allow-popups allow-forms" src="http://www.example.com"</iframe>

With HTML5 the iframe sandbox attribute was added. At the time of writing this works on Chrome, Safari, Firefox and recent versions of IE and Opera but does pretty much what you want:

<iframe src="url" sandbox="allow-forms allow-scripts"></iframe>

If you want to allow top-level redirects specify sandbox="allow-top-navigation".