There are several ways to reload or refresh an iframe using JavaScript:

1. Using the location.reload() method: This method reloads the current document, including any iframes it contains. To reload the iframe only, you can access it using the contentWindow property of the iframe and call the location.reload() method on it:

var iframe = document.getElementById('my-iframe');
iframe.contentWindow.location.reload(true);

In this example, the contentWindow property is used to access the window object of the iframe, and the location.reload() method is called on it with the true argument to force a reload from the server.

2. Using the src attribute: Another way to reload an iframe is to reset its src attribute to the same URL it already has. This causes the iframe to reload its content from scratch:

var iframe = document.getElementById('my-iframe');
iframe.src = iframe.src;

In this example, the src attribute of the iframe is set to its current value, which causes the browser to reload the iframe’s content.

3. Using the location.replace() method: This method is similar to location.reload(), but it replaces the current URL with a new one. To reload the iframe only, you can access it using the contentWindow property of the iframe and call the location.replace() method on it with the current URL:

var iframe = document.getElementById('my-iframe');
iframe.contentWindow.location.replace(iframe.src);

In this example, the location.replace() method is called on the window object of the iframe, with the src attribute of the iframe as the new URL.

All of these methods work in most modern browsers, but some older browsers may have limitations or different behavior when reloading iframes. It’s a good idea to test your code thoroughly and consider using a library or framework that provides a consistent and reliable way to work with iframes.