First, Login On Facebook.

Now go to, https://m.facebook.com/friends/center/requests/outgoing/#friends_center_main

It will display all your pending sent requests.
Open “Inspect” by Right click on the same page.

Now Go to “console” in top tabs and hit below script.

javascript:var inputs = document.getElementsByClassName(‘_54k8 _56bs _56bt’);
for(var i=0; i<inputs.length;i++) {
inputs[i].click();

}

press ENTER

That’s all, all your requests open on that page will be deleted.

(Note: Just ensure to scroll down till all list gets over, this will delete all open requests on the page)