add a javascript action to a link

I have a pdf file with a lot of links, but these links display pages at different size of zoom.
I would like add a javascript action to all these links.
the script below is written for the current page, but the action remove the one setting the target page.
How can I add a second action???
Thanks to let me know.
  
var linkPage = this.pageNum;
var box = this.getPageBox("Crop", linkPage); // get the page box
var linksList = this.getLinks(linkPage, box); // get the link
if (linksList.length > 0)
{
for (var i=0; i < linksList.length; i++) // loop through each link
{
linksList.setAction(this.zoomType=zoomtype.fitP;")
}
}