Just for clarification: is this challenge NOT about having the popup appear, but to see the line on page as text?
If you entered text in the input box which caused an alert box containing a 1 to appear then you've probably got it. Since there is a hard-coded set of accepted solutions, you might have to adjust your answer a bit. Generally, the solution which best guarantees you get points is the one which doesn't result in any invalid HTML.
I also just added another accepted solution now, so maybe try what you tried before again.
That was it, thanks