how we set marker label content by javascript in google map api?

I am using this code this code to change label text of marker label in google map api. But this code not working.

var marker = new MarkerWithLabel({
        position : latlng,
        draggable : true,
        raiseOnDrag : true,
        map : map,
        labelContent : textVal,
        labelAnchor : new google.maps.Point(22, 0),
        title : "" + textCount,
        labelClass : "someClass" + textCount,
        icon:{}
    });
    marker.setLabelContent("sdda");

please can anybody let me know what's wrong in my code?