function showhideblock2(id){
if (document.getElementById){
obj = document.getElementById(id); 
if (obj.style.display == "none"){  
    
    document.getElementById("block-2.1").style.display = "none";
    document.getElementById("block-2.2").style.display = "none";
    document.getElementById("block-2.3").style.display = "none";
    document.getElementById("block-2.4").style.display = "none";

    obj.style.display = "";
    
} else {
obj.style.display = "none"; 
}
}
}