I am developing an adblocker website that allows users to enter a URL and, upon clicking the “Block Ad” button, creates an iframe displaying the website with ads blocked. I understand that completely blocking all ads might not be possible, but I aim to block them using feasible methods. The iframe should occupy 100% width and 100% height (full screen) of the page. Additionally, when users navigate within the iframe or click on links that would normally open in a new tab or window, the content should remain within the iframe.

Could you provide a comprehensive solution including HTML, CSS, and JavaScript code to achieve this functionality? The code should ensure that the entire website is displayed within the iframe under all circumstances.