function gid(a){
 return window.document.getElementById(a);
};

var apos= 1;
function topos(newpos){
      var pvals= new Array("0", "0", "-355", "-720", "-1085", "-1450", "-1815");
      if (pvals.length>newpos && newpos>0){
        var apx = pvals[newpos];
        gid('jak-funguje').style.background="url('images/jft.png') no-repeat "+apx+"px 0px";
        apos= newpos;
      }
      return false;
};