function showBlock(element){

    document.getElementById('a1').style.display = "none";
    document.getElementById('a2').style.display = "none";
    document.getElementById('a3').style.display = "none";
    document.getElementById('a4').style.display = "none";

    
    document.getElementById("a" + element).style.display = "block";
    
    document.getElementById('a1_l').className = "none";
    document.getElementById('a2_l').className = "none";
    document.getElementById('a3_l').className = "none";
    document.getElementById('a4_l').className = "last";

    
    document.getElementById("a" + element + "_l").className = "active";
    if (element > 1) {
        element1 = element - 1;
        document.getElementById("a" + element1 + "_l").className = "none_b";
    }
}

function doPrint(){
    window.print();
}