Add a script to whole site, not appearing

Good Morning,
you can add in the iframe html and put as (error loading) and add a fixed button that shows and hides the iframe html, it will only take up space for click if it is being displayed.

example:

 export function chatbuttom_click() {
 //Add your code for this event here: 
 if ($w("#chatbox").collapsed) {
        $w("#chatbox").expand();
        } else {
        $w("#chatbox").collapse();
    }
}

(chat box) is the ID of the (iframe html)