To trigger the element click after 2 seconds you can do this:
window.setTimeout( function() {
document.getElementById('redirect').click();
}, 2000);
<a id="redirect" onclick="window.history.back()">Go back (auto after 2sec)</a>
or you could do:
window.setTimeout( function() {
window.history.back()
}, 2000);
<a id="redirect" onclick="window.history.back()">Go back (auto after 2sec)</a>