var bstate = true;
var elm = null;

function blink() {
    if (elm != null) {
        if (bstate) {
            elm.style.visibility = 'visible';
            bstate = false;
        } else {
            elm.style.visibility = 'hidden';
            bstate = true;
        }
    } else {
        if (document.all)  {
           elm = document.all('xblink');
        } else if (document.getElementById) {
            elm = document.getElementById('xblink');
        } else if (document.layers) {
            elm = document.layers['xblink'];
        }
    }
    setTimeout('blink()',500);
}