function popUp(URL, x, y) {
	var top=(screen.height-y)/2;
	var left=(screen.width-x)/2;
	var parameter="toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,width=" + x + ",height=" + y + ",top=" + top + ",left=" + left + ",resizable=no";
	window.open(URL, 'popup', parameter);
}

// verif chaine contenant a->z ou A->Z et 0->9 + "-"
function letternumber(e)
{
	var key;
	var keychar;
	if (window.event)
	   key = window.event.keyCode;
	else if (e)
	   key = e.which;
	else
	   return true;
	keychar = String.fromCharCode(key);
	keychar = keychar.toLowerCase();
	
	// control keys
	if ((key==null) || (key==0) || (key==8) ||
		(key==9) || (key==13) || (key==27) )
	   return true;
	
	// alphas and numbers
	else if ((("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_").indexOf(keychar) > -1))
	   return true;
	else
	   return false;
}