function changeBio(el, a) {
 var imageName;
 for (i = 1; i <= 12; i++) {
  imageName = "bio" + i; 
  if (document.getElementById(imageName)) {
   document.getElementById(imageName).style.display='none';
  }
 }
 document.getElementById(el).style.display='block';
 
 var left = document.getElementById('leftnav')
 	var as = left.getElementsByTagName('div');
	for (var i = 0; i < as.length; i++){
		if(as[i].className == 'sel'){
			as[i].className = '';
		}
	}
 a.className='sel';

}