I have two buttons, a left arrow and a right arrow to navigate through my slideshow. The slideshow has several parts. If one part ends the next button hides. But even if it's not visible it's still clickable and that messes up my code because I have a counter. To make it "unclickable" I would like to change the css via jquery to `z-index: -1;` but it doesn't work. I tried following:

```
$('#bx-next').css({"zIndex":"-1"});

```

and also:

```
$('#bx-next').css({zIndex:-1});

```

How to do it right? Didn't find anything on google - but it has to be possible, right?