function switchhook() {

    var thelink = document.getElementById("ouhook").href;

    var lnks = document.links;
    for (var i=0;i<lnks.length;i++) {
        if (lnks[i].id == "copylink") {
            lnks[i].href = thelink;
            break;
        }
    }
}

window.onload = switchhook;