function prodlouzeni() {
  if(window.innerHeight) {
    document.getElementById("telo").style.minHeight = (window.innerHeight - 199) + "px";
  } else {
    document.getElementById("telo").style.height = (document.body.clientHeight - 196) + "px";
  };
}

prodlouzeni();

window.onresize = prodlouzeni;