function updateVille(zone)
{
	var id_region = document.getElementById('sel_region').selectedIndex;
	var region = document.getElementById('sel_region').options[id_region].value;

	var tabCity = new Array();

	//alert ("Region : " + region);
	
	if (region.substring(0,1) == 'r')
	{
		//Choix d'une région
		//alert("Choix = région");
		tabCity = tabCityByRegion[region];		
    }
    else
    {
    	//Choix d'un département
	    //alert("Choix = département");
	    tabCity = tabCityByDepartment[region];
    }
    
    var indexOption = 0;
    document.getElementById('sel_zone').options.length = 0;
	var opt = new Option('', '');
	document.getElementById('sel_zone').options[indexOption] = opt;
	indexOption++;
    for (key in tabCity)
	{
		//alert("Ville : " + tabCity[key] + " (" + key + ")");
		default_select = false;
		if (zone == key)
		{
			//alert("Ville : " + tabCity[key] + " (" + key + ")");
			default_select = true;
		}	

		
		var opt = new Option(tabCity[key] , key, default_select);
		document.getElementById('sel_zone').options[indexOption] = opt;
		indexOption++;
	}
}