function change_class(selected_element){

    for(var i=1; i <= 14; i++){
        if(i == selected_element){
            document.getElementById('frame'+i).className = 'a_active';
        }else{
            document.getElementById('frame'+i).className = '';
        }
    }
    return false;
}

function change_steps(selected_step){
    switch (selected_step){
        case "inscription_info":
            document.getElementById('inscription_info').style.display = 'block';
            document.getElementById('donate').style.display = 'none';
            document.getElementById('confirmation').style.display = 'none';
            break;
        case "donate":
            document.getElementById('inscription_info').style.display = 'none';
            document.getElementById('donate').style.display = 'block';
            document.getElementById('confirmation').style.display = 'none';
            break;
        case "confirmation":
            document.getElementById('inscription_info').style.display = 'none';
            document.getElementById('donate').style.display = 'none';
            document.getElementById('confirmation').style.display = 'block';
            break;
    }
}