function setHNav() {
    var loc = window.location.toString().toLowerCase();
    var hnavs = document.getElementById("hnav").getElementsByTagName("a");
    var isHome = true;
    
    // test for sections other than home.
    for (var i=1; i < hnavs.length; i++) {
        if (loc.indexOf(hnavs[i].href.toString().toLowerCase()) != -1) {
            var img = hnavs[i].getElementsByTagName("img")[0];
            if (img.src.indexOf('off') != -1)
                img.src = img.src.replace('off','on');
            isHome = false;
            break;
        }
    }
    
    if (isHome) {
        var homeNav = hnavs[0].getElementsByTagName("img")[0];
        homeNav.src = homeNav.src.replace('off','on');
    }
}
function setHNavRollOver() {
    var hnavImgs = document.getElementById("hnav").getElementsByTagName("img");
    for (var i=0; i < hnavImgs.length; i++) {
        hnavImgs[i].onmouseover = function(){this.src = this.src.replace('off','roll');};
        hnavImgs[i].onmouseout = function(){this.src = this.src.replace('roll','off');};
    }
}
setHNav();
setHNavRollOver();