function show1(){

              content1.style.display="block";

              content2.style.display="none";

              content3.style.display="none";

}

 

function show2(){

              content1.style.display="none";

              content2.style.display="block";

              content3.style.display="none";

}

 

function show3(){

              content1.style.display="none";

              content2.style.display="none";

              content3.style.display="block";

}