function init_tab () {
    var target = document.getElementById("tabs");
    var coll = target.getElementsByTagName("A");
    for (i=0; i<coll.length; i++) {
        coll[i].onclick = activate;
    }
    document.body.activeNode = coll[1];
    document.getElementById("link_1").className = "active";
    document.getElementById("link_2").className = "link_2";
    //document.getElementById("link_3").className = "link_3";
}
function activate () {
    var id = this.name+"_";
    if (document.body.activeNode) {
        document.body.activeNode.className = document.body.activeNode.id;
        var n = document.body.activeNode.name;
        //document.body.activeNode.firstChild.src = "cab_files/"+n+"_active.gif";

        var p_id = document.body.activeNode.name+"_";
        document.getElementById(p_id).style.display = "none";
    }
    this.className = "active";
    document.body.activeNode = this;
    n = document.body.activeNode.name;
    //document.body.activeNode.firstChild.src = "cab_files/"+n+"_active.gif";
    document.getElementById(id).style.display = "block";
}