var activeTarget = "studieAlgemeen";

// switch between targets (kwartalen)
function studieSwitch(target)
{ 
  // hide current activeTarget and reset anchor color
  document.getElementById(activeTarget).style.display = "none";
  document.getElementById(activeTarget + "Anker").style.color = "#00FF00";
  
  // show new target and anchor color and set new activeTarget
  document.getElementById(target).style.display = "block";
  document.getElementById(target + "Anker").style.color = "#FFFFFF";
  activeTarget = target;
}