How to detect whether a document is inside a iframe with JavaScript Back

Browsers can block access to window.top due to same origin policy. IE bugs also take place. Here's the working code:

function inIframe () {
    try {
        return window.self !== window.top;
    } catch (e) {
        return true;
    }
}

top and self are both window objects (along with parent), so you're seeing if your window is the top window.