function showbox(box_id) {
	var text;
	document.getElementById('overlay').style.display = "block";
	document.getElementById(box_id).style.display = "block";

	window.scrollTo(0,0);
	
	bod = document.getElementsByTagName('body')[0];
	bod.style.height = '100%';
	bod.style.overflow = 'hidden';
  
	htm = document.getElementsByTagName('html')[0];
	htm.style.height = '100%';
	htm.style.overflow = 'hidden';
}

function hidebox(box_id){
	document.getElementById('overlay').style.display = "none";
 	document.getElementById(box_id).style.display = "none";

	bod = document.getElementsByTagName('body')[0];
	bod.style.height = 'auto';
	bod.style.overflow = 'auto';
  
	htm = document.getElementsByTagName('html')[0];
	htm.style.height = 'auto';
	htm.style.overflow = 'auto';
	
	document.getElementById('myspan').innerHTML = "";            

}