[monolithed]

Ну примерно как-то так:

<script type="text/javascript">
window.onload = function(){
    var element = document.getElementsByTagName('a'), i = element.length;
    while(i--){   
        element[i].onclick = function(i){
            return function(){
                document.getElementsByTagName('div')[0].style.display = i == 0 ? 'block' : 'none';
            };
        }(i);
    }
};
</script>

<style type="text/css">
div {
    background: #B3D5DE;
    display: none;
    opacity:0.5;
    position: absolute;
    top: 10px;
    left: 10px;
    width: 200px;
    height: 200px;
}
    
div a {
    display: block;
    cursor: pointer;
    color: #000;
    float: right;
    font: bold 18px arial;
    position: relative;
    text-decoration: none;
}
div a:hover {
    color: red;
}
</style>

<a href="#">click</a>
<div><a href="#">&otimes</a></div>