The documentation says this.
If you want to show avgrund on page load set this option value to false, example:
$(document).avgrund({
openOnEvent: false
});
Which I suppose should be in document ready.
$(function() {
$(document).avgrund({
openOnEvent: false
});
});
That will open automatically on page load.
I just copied the files and it worked straight away for me (having never seen it before).