function showteachers (){
document.getElementById("nav1").style.display = 'block';
document.getElementById("nav2").style.display = 'none';
document.getElementById("nav22").style.display = 'block';
document.getElementById("nav11").style.display = 'none';
}
function showcredentials1(){
document.getElementById("nav2").style.display = 'block';
document.getElementById("nav1").style.display = 'none';
document.getElementById("nav33").style.display = 'block';
document.getElementById("nav22").style.display = 'none';
}
function showcredentials(){
document.getElementById("nav2").style.display = 'block';
document.getElementById("nav1").style.display = 'none';
document.getElementById("nav33").style.display = 'block';
document.getElementById("nav11").style.display = 'none';
}
function showcorporation(){
document.getElementById("nav3").style.display = 'block';
document.getElementById("nav4").style.display = 'none';
document.getElementById("nav55").style.display = 'block';
document.getElementById("nav44").style.display = 'none';
}
function showstudent1(){
document.getElementById("nav4").style.display = 'block';
document.getElementById("nav3").style.display = 'none';
document.getElementById("nav66").style.display = 'block';
document.getElementById("nav55").style.display = 'none';
}
function showstudent(){
document.getElementById("nav4").style.display = 'block';
document.getElementById("nav3").style.display = 'none';
document.getElementById("nav66").style.display = 'block';
document.getElementById("nav44").style.display = 'none';
}