Edit in JSFiddle

for (var n = 0; n < 5; n++) {
    document.getElementsByTagName("input")[n].onclick = function() {
        document.getElementsByTagName("div")[0].style.borderWidth = this.value + "px";
    };
}

<input type="radio" name="width" value="20" />20
<input type="radio" name="width" value="30" />30
<input type="radio" name="width" value="40" />40
<input type="radio" name="width" value="50" />50
<input type="radio" name="width" value="60" />60
<div></div>

div {
    width:75px;
    height:75px;
    border-color:#f0eb7a #f0eb7a #12ad2a #f0eb7a;
    border-style:solid;
    border-width:20px;
    -moz-border-radius:50px;
}