JavaScript Bouton Radio et Input

<SCRIPT type="text/javascript">

function shiftOpacity(id, millisec) {

    //if an element is visible, make it invisible, else make it invisible
    if(document.getElementById(id).style.opacity != 0) {
        opacity(id, 100, 0, millisec);
    } else {
         opacity(id, 0, 100, millisec);

    }
} 


function opacity(id, opacStart, opacEnd, millisec) {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;

    //determine the direction for the blending, if start and end are the same nothing happens
    if(opacStart > opacEnd) {
        for(i = opacStart; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    } else if(opacStart < opacEnd) {
        for(i = opacStart; i <= opacEnd; i++)
            {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    }
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
    var object = document.getElementById(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
} 
</script>

<a href="javascript:shiftOpacity('opacity', 1000)">Artiste</a>

#opacity
{
border: 0px solid green;
opacity: 0;
filter : alpha(opacity=0); 
color: #292929;
text-align: center;
margin-left: auto;
margin-right: auto;
width: 100%;
}

#opacity a
{
color: black;
}