var ob = document.getElementById("ifs_2"); 
if ( ob ) {
    if (anc>2) {
        var half_ = document.getElementById("ifs_2").clientWidth/2;
        var left1_ = document.getElementById("ifs_2").offsetLeft;
        var left2_ = document.getElementById("tsmenu").offsetLeft;
        var left3_ = document.getElementById("tssmenu").offsetLeft;
        var width_ = document.getElementById("tssmenu").clientWidth/2;
        var tssmenu = document.getElementById("tssmenu");
        tssmenu.style.left = (left1_ + half_ + left2_ - left3_ - width_)+"px";
    }
}