leaflet zoomer problem

zoomer!

The correct 'link':
<div class='map-navigation'  data-zoom='12' data-position='<%=d.tractlat%>,<%=d.tractlon%>'>Zoom</div>

The 'link' that zoomed but then reloaded page:
<div class='map-navigation'><a href='' data-zoom='12' data-position='<%=d.tractlat%>,<%=d.tractlon%>'>Zoom</a></div>

The zoomer function:
document.querySelector('.map-navigation').onclick = function(abc) {
    var pos = abc.target.getAttribute('data-position');
    var zoom = abc.target.getAttribute('data-zoom');
    if (pos && zoom) {
        var locat = pos.split(',');
        var zoo = parseInt(zoom);
    map.setView(new L.LatLng (locat[0], locat[1]), zoo, {animation: true});
    return false;
    }
};

loaded params inside div, not an a href, function performs onclick...