function showSchema()
{
    var schema = document.getElementById('schema');
    var schema_src = document.getElementById('schema_src');
        schema.style.zIndex = 1;      
        schema.style.display = 'block'; 
    
    vs = getBrowserVersion();
    
    if (vs[0] == 'MSIE' && vs[1] < 8)
    {
        var ctl = document.getElementById('midden');
            schema.style.left = '268px';
    }
    var menuitems = document.getElementById('menuitems');
        menuitems.style.display = 'none';
    return false;
}

function hideSchema()
{
    var schema = document.getElementById('schema');
        schema.style.display = 'none';
    var menuitems = document.getElementById('menuitems');
        menuitems.style.display = 'block';
}

function getBrowserVersion()
{
    var vs = navigator.appVersion;
    var i = vs.indexOf('(');
       vs = vs.substr(i + 1, vs.length - i - 1);
       vs = vs.split(';')[1]
       vs = vs.split(' ');
    return [vs[1], parseInt(vs[2])];
}