There is in the HTML file string, for example:
Please note, use the async attribute.
But even if it is used, the browser then uses the icon of the page loading, and for example, if the server is hung, then this script will be loaded very long.
Is it possible to do this if the server is unavailable or responding too long, the user was not visible, something else is connected?
That is, we need the background to load the script, but that it had no effect on the browser interface.