var illLargeCurrent = null;
var illLargeNew = null;
var illSmallCurrent = null;
var illSmallNew = null;
function showIllustration(illId) 
{
    illLargeNew = document.getElementById('ill-large-' + illId);
    if(illLargeNew != illLargeCurrent) 
    {
        if(illLargeCurrent) 
        {
            illLargeCurrent.style.display = 'none';
        }
        if(illLargeNew) 
        {
            illLargeNew.style.display = 'block';
            illLargeCurrent = illLargeNew;
        }
    }
    
}
function closeIllustration(illId) 
{
    illLargeCurrent = document.getElementById('ill-large-' + illId);
    illLargeCurrent.style.display = 'none';
    illLargeCurrent = null;
}