How can we handle model popups in advanced loadtesting

Hi ,
I have a scenario to do some actions in model popup how can i handle this ?

Thanks in advance

Load testing is not about what you see, but what the site does internally and on the network. So a modal popup (not a JS popup!) is in most cases similar to an add to cart via XHR for instance. But what you probably want to is, to get the HTML from the response and put it into the page, so you can interact with it later? Do you have a more concrete example aka a site impl to touch?