// thanx nipotan.
function getElementsByClass(searchClass) {
    var classElements = new Array();
    var allElements = document.getElementsByTagName("*");
    for (i = 0, j = 0; i < allElements.length; i++) {
        if (allElements[i].className == searchClass) {
            classElements[j] = allElements[i];
            j++;
        }
    }
    return classElements;
}

var nodes = getElementsByClass("asin");

function asin2amazonbox () {
        for (var i = 0; i < nodes.length; i++) {
                var asin = nodes[i].innerHTML;
                nodes[i].innerHTML = '<iframe src="http://rcm-jp.amazon.co.jp/e/cm?t=hippofm-22&o=9&p=8&l=as1&asins=' + asin + '&fc1=000000&IS2=1&lt1=_blank&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="width:120px;height:240px;" scrolling="no" marginwidth="0" marginheight="0" frameborder="0"></iframe>';
                nodes[i].style.visibility = "visible";
        }
}

asin2amazonbox();