I prefer doing something like:
Code:
if (! $(body).hasClass('Responsive') ) {
//code when responsive is turned off
}
But there are many ways to do it.
ETA: Nevermind, I see what you mean now. The way Chris has it is good. But instead, use 800px as thats when XenForo (by default, but this can be changed in Style Properties).
The way I have it is for if responsive is toggled off entirely.