Question: If I use `(body).height();` to calculate a windows height, is there a way to calculate the height -100px. 

Is there a way to do this as part of the `(body).height();` query rather than calculating it later on ?

Answer: 
```
($(body).height() - 100)

```

Just... subtract?
If you don't want to calculate it each time and deducting 100, you can define a custom function that will do it for you:

```
function bodyHeight() {
    return $("body").height()-100;
}

```

And then just call `bodyHeight()` instead of `$("body").height()`.