Fade out multiple Bootstrap alerts

Fade out multiple Bootstrap alerts

I came across a question asking how to fade out Bootstrap alerts after 5
seconds, and the answer was the following code. The issue is, it only
works once, however as I have multiple alerts that are generated after an
AJAX call this is no good. How do I make the following code run every time
an alert is triggered?
window.setTimeout(function() {
$(".alert").fadeTo(500, 0).slideUp(500, function(){
$(this).remove();
});
}, 5000);