function ShowAndHide(id1,id2){
if(document.getElementById){
    el1=document.getElementById(id1);
    el2=document.getElementById(id2);
    if(el1.style.display=="none"){
        el1.style.display="block";
        el2.style.display="none";
        }
    else{
        el1.style.display="none";
        el2.style.display="block";
        }
    }
}