How Can We Detect If a Webpage Is Loaded Inside an IFrame?

Identifying Iframe Loading for Multi-Purpose Webpage

In the realm of web development, differentiating between a webpage loaded within an iframe and directly in a browser window is often a crucial task. This is especially relevant for applications that aim to serve multiple purposes, such as rendering both a normal website and a canvas page within Facebook. To address this challenge, we explore methods to determine the webpage's loading environment.

Detecting Iframe Loading

To ascertain whether a webpage is loaded within an iframe, we can leverage the differences between window objects. In particular, the self property represents the current window, while the top property denotes the outermost window or frame. If these two window objects are not identical, it implies that the webpage is loaded within an iframe.

Code Implementation

const inIframe = () => window.self !== window.top;

This function returns a boolean value indicating whether the page is loaded inside an iframe. A true value denotes iframe loading, while a false value signifies direct loading in the browser window.

Update for Cross-Origin Access

Browser security measures may restrict access to window.top due to the same-origin policy. To address this issue, a try-catch block can be employed:

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

In this updated version, an exception caused by blocked access to window.top is handled by assuming iframe loading.

Conclusion

By understanding the differences between window objects, we have established methods to reliably detect whether a webpage is loaded within an iframe. This knowledge empowers developers to create applications that adapt their behavior based on the loading environment, ensuring seamless functionality across various platforms.

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