function showElement1()
{
document.getElementById("content1").style.visibility="visible";
document.getElementById("content2").style.visibility="hidden";
document.getElementById("content3").style.visibility="hidden";
document.getElementById("content4").style.visibility="hidden";
document.getElementById("content5").style.visibility="hidden";
}

function showElement2()
{
document.getElementById("content1").style.visibility="hidden";
document.getElementById("content2").style.visibility="visible";
document.getElementById("content3").style.visibility="hidden";
document.getElementById("content4").style.visibility="hidden";
document.getElementById("content5").style.visibility="hidden";
}

function showElement3()
{
document.getElementById("content1").style.visibility="hidden";
document.getElementById("content2").style.visibility="hidden";
document.getElementById("content3").style.visibility="visible";
document.getElementById("content4").style.visibility="hidden";
document.getElementById("content5").style.visibility="hidden";
}

function showElement4()
{
document.getElementById("content1").style.visibility="hidden";
document.getElementById("content2").style.visibility="hidden";
document.getElementById("content3").style.visibility="hidden";
document.getElementById("content4").style.visibility="visible";
document.getElementById("content5").style.visibility="hidden";
}

function showElement5()
{
document.getElementById("content1").style.visibility="hidden";
document.getElementById("content2").style.visibility="hidden";
document.getElementById("content3").style.visibility="hidden";
document.getElementById("content4").style.visibility="hidden";
document.getElementById("content5").style.visibility="visible";
}

function showVideo()
{
document.getElementById("content1").style.visibility="hidden";
document.getElementById("content2").style.visibility="hidden";
document.getElementById("content3").style.visibility="hidden";
document.getElementById("content4").style.visibility="hidden";
document.getElementById("content5").style.visibility="hidden";
document.getElementById("menu").style.visibility="hidden";
document.getElementById("header").style.visibility="hidden";
document.getElementById("showweb").style.visibility="visible";
document.getElementById("showvideo").style.visibility="hidden";
}

function showSite()
{
document.getElementById("content1").style.visibility="visible";
document.getElementById("content2").style.visibility="hidden";
document.getElementById("content3").style.visibility="hidden";
document.getElementById("content4").style.visibility="hidden";
document.getElementById("content5").style.visibility="hidden";
document.getElementById("menu").style.visibility="visible";
document.getElementById("header").style.visibility="visible";
document.getElementById("showweb").style.visibility="hidden";
document.getElementById("showvideo").style.visibility="visible";
}