Will populate active input field with "turlututu+<domain name>@gmail.com"
Code:
javascript:(function()%7Bvar%20w%3Dwindow.location.hostname.replace(%2F%5Ewww%5C.%2F%2C'')%3Bw%20%3D%20w.replace(%2F%5C..%7B2%2C3%7D%2F%2C'')%3Bvar%20i%20%3D%20document.activeElement%3Bif%20(i.tagName%20%3D%3D%20%22INPUT%22%20%7C%7C%20i.tagName%20%3D%3D%20%22TEXTAREA%22)%7Bi.value%20%3D%20'turlututu%2B'%2Bw%2B'%40gmail.com'%3B%7D%7D)()
Expanded: