window.onload=function(){
	document.getElementById("navigation").style.visibility = 'hidden';
	document.getElementById("footer").style.visibility = 'hidden';
	document.getElementById("project").style.visibility = 'hidden';	
	Check();
}


function intro(){
	document.getElementById("navigation").style.visibility = 'visible';
	document.getElementById("footer").style.visibility = 'visible';
	document.getElementById("project").style.visibility = 'visible';	
	document.getElementById("content-row2").style.display = 'none';
}





var Dauer = 10*60; // Gültigkeit des Cookies in Sekunden

function CookieLesen(name)
{
    var arg = name + "=";
    var alen = arg.length;
    var clen = document.cookie.length;
    var i = 0;

    while (i < clen)
    {
        var j = i + alen;

        if (document.cookie.substring(i, j) == arg)
        {
            return CookieEinlesen (j);
        }

        i = document.cookie.indexOf(" ", i) + 1;

        if (i == 0)
        {
            break;
        }
    }

    return null;
}


function CookieSetzen(name, value)
{
    var argv = CookieSetzen.arguments;
    var argc = CookieSetzen.arguments.length;
    var expires = (argc > 2) ? argv[2] : null;
    var path = (argc > 3) ? argv[3] : null;
    var domain = (argc > 4) ? argv[4] : null;
    var secure = (argc > 5) ? argv[5] : false;
    document.cookie = name + "=" + escape (value) + ((expires == null) ? "" : ("; expires=" + expires.toGMTString())) + ((path == null) ? "" : ("; path=" + path)) + ((domain == null) ? "" : ("; domain=" + domain)) + ((secure == true) ? "; secure" : "");
}


function CookieLoeschen(name)
{
    var exp = new Date();
    exp.setTime(exp.getTime() - 1);
    var cval = CookieLesen (name);
    document.cookie = name + "=" + cval + "; expires=" + exp.toGMTString();
}


var exp = new Date();
exp.setTime(exp.getTime() + (Dauer*1000));


function CookieEinlesen(offset)
{
    var endstr = document.cookie.indexOf (";", offset);

    if (endstr == -1)
    {
        endstr = document.cookie.length;
    }

    return unescape(document.cookie.substring(offset, endstr));
}


function Check()
{
    var count = CookieLesen('CheckIntro');

    if (count == null)
    {
        count = 1;
        CookieSetzen('CheckIntro', count, exp);
    }
    else
    {
        count++;
        CookieSetzen('CheckIntro', count, exp);
        intro();
    }
}