No. The URL specified by the src
attribute is used to make a GET request.
You can get the results of a POST request to display in an iframe, but that requires that you submit a form with target="name_of_iframe"
and not just use the src
attribute.
It's possible to hack this by submitting such a form with JS on page load.
That said, POST requests are designed for sending a request to change/add data on the server. They aren't generally useful unless the user is entering data into a form. Thus triggering a POST request as a soon as a page loads doesn't usually make any sense. You should probably be reevaluating the desire for a POST request here in the first place.