javascript to open links in umap marker description in parent page containing the iframe

Hello everybody,

other people seem to have had this problem already, but I could not find a viable solution for my case. I have a UMap with some location markers that show projects. This UMap is shown in an iframe embedded on the projects' website. Each project has its own page with detailed information. I have put a link to each project's page in the marker description, but I would like these links to open in the window with the iframe page, since they are all on the same website.

I found a little script on the web which I tried:

function onLoadIF(frame)
{
    var elements = frame.getElementsByTagName('a'),
        len = elements.length;

    while( len-- ) {
        elements[len].target = "_parent";
    }
}

This doesn't work however, since the map is also generated by javascript. Is there any way of accessing those links in the descriptions by javascript so I can change their targets?

Many thanks in advance for your ideas and help!