var old_letter = "";
var glossary = "glossaire_";
	
if (old_letter == "")
	{
		old_letter = "A";
	}

function display_letter(letter) {
	
	var div2display = glossary + letter;
	var div2hide = glossary + old_letter;
	
	if (document.getElementById && document.getElementById(div2display) != null && document.getElementById(div2hide) != null)
		{				
			//document.getElementById(div2display).style.visibility='visible';
			document.getElementById(div2hide).style.display = 'none';		
			document.getElementById(div2display).style.display = 'block';
			old_letter = letter;
		}			
}