function ShowHide(div){//use this function to allow people to show multiply div tags.
		
	if (document.getElementById(div).style.display == 'none' ){
		document.getElementById(div).style.display = 'block';	
	}
	else if ( document.getElementById(div).style.display == 'inline-block' ){
		document.getElementById(div).style.display = 'none';
	}
	else
	{
		document.getElementById(div).style.display = 'none';
	}
}

function toggleSlide ( id ) {//use this funciton to only allow one div tag to be displayed at once
  for ( var f = 2005; f <= 2020; f ++ ) {
    if ( node = document.getElementById(f) ) {
      if ( f == id ) {
        node.style.display = 'block'; 
      } else {
        node.style.display = 'none';
      }
    }
  }
}