[monolithed]

Djohan какой же вы не самостоятельный:

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window.onload = function(){
     var a = document.getElementsByTagName('a'), i = a.length;
     while(i--){
          a[i].onclick = function(i){
             var dt = document.getElementsByTagName('dt');
              return function(){
                 dt[i].style.display = (dt[i].style.display == '') ? 'block' : '';
              };
          }(i);
     }
 };
</script>

<style type="text/css">
dl, dt, dd {margin: 0px;  padding: 0px;}
dl {border: 1px solid #DDD; float: left; margin-right: 10px; padding: 0px; width: 50px;}
dd, dt {text-align: center;}
dt {background: red; display: none; width: 50px; height: 50px;}
</style>

<dl>
    <dd><a href="#">click</a></dd>
    <dt>1</dt>
</dl>
<dl>
     <dd><a href="#">click</a></dd>
     <dt>2</dt>
</dl>