/*
** show or hide element e depending on condition show
*/
function toggle(e, show)
{
	e.style.display = show ? '' : 'none';
}

/**
* Show dynamicaly an element by changing the sytle "display" property
* depending on the option selected in a select.
*
* @param string $select_id id of the select who controls the display
* @param string $elem_id prefix id of the elements controlled by the select
*   the real id must be : 'elem_id'+nb with nb the corresponding number in the
*   select (starting with 0).
*/
function showElemFromSelect(select_id, elem_id)
{
	var select = document.getElementById(select_id);
	for (var i = 0; i < select.length; ++i)
	{
	    var elem = document.getElementById(elem_id + select.options[i].value);
		if (elem != null)
			toggle(elem, i == select.selectedIndex);
	}
}