function ToggleVisibility(image, element){
    // Find the image.
    var image = document.getElementById(image)
    
    // Find the element to hide/unhide.
    var element = document.getElementById(element)

    // Check the element's current state.
    if (element.style.display == "none"){
      // If hidden, unhide it.
      element.style.display = "block"
      image.src = "images/open.png"
    }
    else
    {
      // If not hidden, hide it.
      element.style.display = "none"
      image.src = "images/closed.png";
    }
  }