Hi,
That code is javascript, so you’ll need to know how to write some javascript on the page in order to use it.
Also the code has to be called when the slider is displayed – that depends on the ‘display’ event for the slider control, which is different for every slider.
You could also try the CSS workaround of positioning the hidden element off-screen.
Unfortunately, there’s no general answer. It depends on what type of plugin/control you’re using for the slider.
Here’s a link to the jQuery page explaining the same thing for their tabs control:
There are millions of hits about this problem on Google. Maybe someone has already found a a solution for that particular slider?