function resetClass ()
{
document.getElementById("content2a").setAttribute("class", "nothing");
document.getElementById("content3a").setAttribute("class", "nothing");
}

function removeStudentElements()
{
document.getElementById("content_1").style.display="none";
document.getElementById("content_2").style.display="none";
document.getElementById("content_3").style.display="none";
}

function showStudentContent_2()
{
removeStudentElements();
document.getElementById("content_2").style.display="block";
resetClass();
document.getElementById("content2a").setAttribute("class", "current");
}

function showStudentContent_3()
{
removeStudentElements();
document.getElementById("content_3").style.display="block";
resetClass();
document.getElementById("content3a").setAttribute("class", "current");
}