function getElementsByClass(searchClass, domNode, tagName) {
    if (domNode == null) domNode = document;
    if (tagName == null) tagName = '*';
    var el = new Array();
    var tags = domNode.getElementsByTagName(tagName);
    var tcl = searchClass;
    for(i=0,j=0; i<tags.length; i++) {
        var test = tags[i].className;
        if (test.indexOf(tcl) != -1) el[j++] = tags[i];
    }
    return el;
}

function doIt(){
    var elms = getElementsByClass('blink');
    for(i=0; i<elms.length; i++) 
        elms[i].style.visibility = (elms[i].style.visibility == "hidden") ? "visible" : "hidden";
}

function Knipper(){
    setInterval('doIt()',700);
}
window.onload = Knipper;