[Slashcode-general] help: javascript inside a block

[Francesco O. <pro...@pr...>]

we are developing a new slash site ( http://www.dsmodena.it  ) and we ask
you to solve a problem,

we would like to put inside a block a news scroller made with javascript
but you can see that if you go to an other web page without this block, we
receive a javascript error (you can test it),

how can we solve this trouble?
is it posssible to insert  a variable to tell javascript not to run if
there is not the block?
and if yes, how?

sorry for our english -------

bye,
Francesco (ITALY)