function roll_over(img_name, img_src)
{
    var ele = document.getElementById(img_name);
    ele.src = img_src;
   
}

function showSecNav()
{
    hideSecNavs();
    document.getElementById('secNav').style.visibility = 'visible';
}
function showSecNav1() {
    hideSecNavs();
    document.getElementById('secNav1').style.visibility = 'visible';
}

function showSecNav2()
{
    hideSecNavs();
    document.getElementById('secNav2').style.visibility = 'visible';
}
function showSecNav3()
{
    hideSecNavs();
    if(document.getElementById('secNav3'))
        document.getElementById('secNav3').style.visibility = 'visible';
}
function showSecNav4() {
    
    hideSecNavs();
    if (document.getElementById('secNav4'))
        document.getElementById('secNav4').style.visibility = 'visible';
}
function showSecNav5() {

    hideSecNavs();
    if (document.getElementById('secNav5'))
        document.getElementById('secNav5').style.visibility = 'visible';
}
function hideSecNavs()
{

    if (document.getElementById('secNav'))
        document.getElementById('secNav').style.visibility = 'hidden';
    if (document.getElementById('secNav1'))
        document.getElementById('secNav1').style.visibility = 'hidden';
    if (document.getElementById('secNav2'))
        document.getElementById('secNav2').style.visibility = 'hidden';
    if(document.getElementById('secNav3'))
        document.getElementById('secNav3').style.visibility = 'hidden';
    if (document.getElementById('secNav4'))
        document.getElementById('secNav4').style.visibility = 'hidden';
    if (document.getElementById('secNav5'))
        document.getElementById('secNav5').style.visibility = 'hidden';  
        
}