Paul Ilbrink release a year ago a useful script to auto join sessions in iRacing. I copied his announcement.
iRacing Auto Join is a simple userscript that adds a little functionality to the session signup process on the iRacing membersite.
It adds a checkbox after signing up for a session.
When it’s ticked and the green join button appears it automatically clicks it for you so the sim will start loading.
This gives you a bit of extra time to visit the toilet, grab a drink or a snack or whatever you like to do during the minutes before a race.
It works for all type of sessions, whether you’re driving, spectating or spotting.
Chrome | Tamper Monkey
Firefox | GreaseMonkey
Just click this link. If you have installed the corresponding addon/extension you should get a prompt where you can confirm you want to install the script.