Here are the three easy steps:
1) Make a .js text file like this:
var presenturl = window.location.href;
var newurl = presenturl + ‘&t=1m10s’;
2) Upload the .js file to your server.
I am not sure I’ve done this right, but the random number generation starting the .js is meant to force it to refresh each time it is loaded, rather than having the .js get loaded from a browser’s cached files. That means any updates to the .js file will immediately be picked up by anyone using it; or, in other words, web surfers won’t need to clear their cache to get the most recent tweaks to the code.
If you want to see other YouTube parameters you could append to a URL, go here: http://www.techairlines.com/youtube-parameters/#master-web
Finally, why did I discover this at all? Mainly to make using Plone, a CMS, more efficient. In that particular software, getting from an article’s presentation mode to the mode of editing its HTML took two clicks, and a long wait for each click to load. Now I click once and get the HTML editing screen.