How to design click on a div, other div to make corresponding response

<div id= "Show" >
     <div>1</div>
     <div>2</div>
     <div>3</div>
     </div>

    <div id= "click" >
    <div>click1</div>
    <div>click2</div>
    <div>click3</div>
    </div>

Requirements: 1, click Click1,show corresponding display 1 (2,3 disappear)
           2, meanwhile, Click1 's style changes
           3, click Other click, show similar

<script type= "Text/javascript" >window.onload=function() {    varClick_divs = document.getElementById ("click"). getElementsByTagName ("Div"); varShow_divs = document.getElementById ("Show"). getElementsByTagName ("Div");  for(vari = 0; i < click_divs.length; i++) {        !function(a) {//Click #click DivClick_divs[a].onclick =function() {                //#show div all hidden                 for(varx = 0; x < show_divs.length; X + +) {Show_divs[x].style.display= "None"; }                //corresponding #show div displayShow_divs[a].style.display = "Block"; //#click div Style restore                 for(vary = 0; Y < show_divs.length; y++) {Click_divs[y].style.fontweight= "Normal"; }                //corresponding #click div style boldClick_divs[a].style.fontweight = "Bold";        };    } (i); }};</script>

How to design click on a div, other div to make corresponding response