function labs()
 {
  _form = document.getElementById('materials')
  while(_form.hasChildNodes()) _form.removeChild(_form.childNodes.item(0))

  _input = document.createElement('INPUT')
  _input.type = 'hidden'
  _input.name = 'show'
  _input.value = 'lab_'
  _form.appendChild(_input)

  _input = document.createElement('INPUT')
  _input.type = 'hidden'
  _input.name = 'title'
  _input.value = 'Lab Assignments'
  _form.appendChild(_input)

  _form.submit()
 }

 function lectures()
 {
  _form = document.getElementById('materials')
  while(_form.hasChildNodes()) _form.removeChild(_form.childNodes.item(0))

  _input = document.createElement('INPUT')
  _input.type = 'hidden'
  _input.name = 'show'
  _input.value = 'lecture_notes_'
  _form.appendChild(_input)

  _input = document.createElement('INPUT')
  _input.type = 'hidden'
  _input.name = 'title'
  _input.value = 'Lecture Notes'
  _form.appendChild(_input)

  _form.submit()
 }

 function projects()
 {
  _form = document.getElementById('materials')
  while(_form.hasChildNodes()) _form.removeChild(_form.childNodes.item(0))

  _input = document.createElement('INPUT')
  _input.type = 'hidden'
  _input.name = 'show'
  _input.value = 'final_project.'
  _form.appendChild(_input)

  _input = document.createElement('INPUT')
  _input.type = 'hidden'
  _input.name = 'show'
  _input.value = 'term-project.'
  _form.appendChild(_input)

  _input = document.createElement('INPUT')
  _input.type = 'hidden'
  _input.name = 'show'
  _input.value = 'projects.'
  _form.appendChild(_input)

  _input = document.createElement('INPUT')
  _input.type = 'hidden'
  _input.name = 'title'
  _input.value = 'Term Projects'
  _form.appendChild(_input)

  _form.submit()
 }