function zoom (url1,url2,elemId, zoomLink)
{

    if (document.getElementById(zoomLink).firstChild.data == "Zoom In") {
        document.getElementById(zoomLink).firstChild.data = "Zoom Out";
        document.getElementById(elemId).src=url1;
    }
    else {
        document.getElementById(zoomLink).firstChild.data = "Zoom In";
        document.getElementById(elemId).src=url2;
    }
}