function zakladka(element)

{

document.getElementById("a1").style.display = "none";

document.getElementById("a2").style.display = "none";

document.getElementById("a"+element).style.display = "block";

document.getElementById("a1_l").className= "none";

document.getElementById("a2_l").className = "none";

document.getElementById("a"+element+"_l").className="active"; }