framebuster

A framebuster is a JavaScript technique used to prevent a website from being displayed within an iframe or frame on another website. This is typically achieved by checking if the current page is loaded within a frame. If it is, the script will redirect the user's browser to the top-level window, effectively breaking out of the frame and displaying the content in its intended context.

The primary reason for implementing framebusting is to combat "clickjacking" or "UI redressing" attacks. In such attacks, a malicious website might embed a legitimate website within an iframe and overlay invisible elements on top of the iframe. Users are then tricked into clicking on these invisible elements, which actually interact with the hidden framed website, leading to unintended actions like making purchases, revealing sensitive information, or changing settings. By preventing their site from being framed, website owners can mitigate these risks.

Another reason for framebusting can be to protect copyrighted content or ensure that advertisements are displayed correctly and aren't obscured or bypassed. Some content providers may not want their material to be displayed on third-party sites without their explicit permission or control.

While effective, framebusting can sometimes interfere with legitimate uses of frames, such as in certain portal websites or content management systems that rely on framing for their functionality. Modern web security practices have also introduced other methods like the Content Security Policy (CSP) directive `frame-ancestors` which offers a more robust and standardized way to control framing.