function selectOptionByValue(selectName, valueSearched) {
	selectItem = document.getElementById(selectName);
	for (i=0; i<selectItem.options.length; i++)
		if (selectItem.options[i].value == valueSearched)
			return i;
	return -1;
} // selectOptionByValue(...)


function changeOptionByValue(selectName, valueSearched) {
	position = selectOptionByValue(selectName, valueSearched);

	if (position == -1)
		return false;
	
	selectItem.selectedIndex = position;
	
	return true;
} // changeOptionByValue(...)