How can I remove all text inside parentheses inside a div inside an iframe triggered by a modal? [closed]

I have a modal that loads an iframe with dynamic content and I would like to remove any text that appears inside parentheses?

$(document).ready(function() {
    $('iframe').on('load', function() {
        $("iframe").contents().find("#myDiv") /// = then remove all text inbetween () parentheses in that div id content text? ///
    });
}); 

I have tried a few ways like above, but nothing seems to work.

The iframe is on the same domain (my site).